| Network Working Group | M. Boucadair |
| Internet-Draft | Orange |
| Intended status: Standards Track | S. Sivakumar |
| Expires: February 24, 2018 | Cisco Systems |
| C. Jacquenet | |
| Orange | |
| S. Vinapamula | |
| Juniper Networks | |
| Q. Wu | |
| Huawei | |
| August 23, 2017 |
A YANG Data Model for Network Address Translation (NAT) and Network Prefix Translation (NPT)
draft-ietf-opsawg-nat-yang-02
For the sake of network automation and the need for programming Network Address Translation (NAT) function in particular, a data model for configuring and managing the NAT is essential. This document defines a YANG data model for the NAT function.
NAT44, Network Address and Protocol Translation from IPv6 Clients to IPv4 Servers (NAT64), Customer-side transLATor (CLAT), Explicit Address Mappings for Stateless IP/ICMP Translation (SIIT EIM), and IPv6 Network Prefix Translation (NPTv6) are covered in this document.
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."
This Internet-Draft will expire on February 24, 2018.
Copyright (c) 2017 IETF Trust and the persons identified as the document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
This document defines a data model for Network Address Translation (NAT) and Network Prefix Translation (NPT) capabilities using the YANG data modeling language [RFC6020].
Traditional NAT is defined in [RFC2663], while Carrier Grade NAT (CGN) is defined in [RFC6888]. Unlike traditional NAT, the CGN is used to optimize the usage of global IP address space at the scale of a domain: a CGN is not managed by end users, but by service providers instead. This document covers both traditional NATs and CGNs.
This document also covers NAT64 [RFC6146], customer-side translator (CLAT) [RFC6877], Explicit Address Mappings for Stateless IP/ICMP Translation (EAM) [RFC7757], and IPv6 Network Prefix Translation (NPTv6) [RFC6296].
Sample examples are provided in Appendix A.
This document makes use of the following terms:
The usage of the term NAT in this document refers to any NAT flavor (NAT44, NAT64, etc.) indifferently.
This document uses the term "session" as defined in [RFC2663] and [RFC6146] for NAT64.
The meaning of the symbols in these diagrams is as follows:
The NAT YANG data model is designed to cover dynamic implicit mappings and static explicit mappings. The required functionality to instruct dynamic explicit mappings is defined in separate documents such as [I-D.boucadair-pcp-yang]. Considerations about instructing explicit dynamic means (e.g., [RFC6887], [RFC6736], or [RFC8045]) are out of scope.
A single NAT device can have multiple NAT instances; each of these instances is responsible for serving a group of internal hosts. This document does not make any assumption about how internal hosts are associated with a given NAT instance.
The data model assumes that each NAT instance can be enabled/disabled, be provisioned with a specific set of configuration data, and maintains its own mapping tables.
To accommodate deployments where [RFC6302] is not enabled, this YANG model allows to instruct a NAT function to log the destination port number. The reader may refer to [I-D.ietf-behave-ipfix-nat-logging] which provides the templates to log the destination ports.
The following modes are supported:
[I-D.ietf-softwire-dslite-yang] specifies an extension to support DS-Lite.
This document assumes [RFC4787][RFC5382][RFC5508] are enabled by default.
Furthermore, the data model relies upon the recommendations detailed in [RFC6888] and [RFC7857].
The module is structured to support other protocols than UDP, TCP, and ICMP. The mapping table is designed so that it can indicate any transport protocol. For example, this module may be used to manage a DCCP-capable NAT that adheres to [RFC5597].
Future extensions can be defined to cover NAT-related considerations that are specific to other transport protocols such as SCTP [I-D.ietf-tsvwg-natsupp]. Typically, the mapping entry can be extended to record two optional SCTP-specific parameters: Internal Verification Tag (Int-VTag) and External Verification Tag (Ext-VTag).
This data model assumes that blocks of IP external addresses (external-ip-address-pool) can be provisioned to the NAT function. These blocks may be contiguous or not.
This behavior is aligned with [RFC6888] which specifies that a NAT function should not have any limitations on the size or the contiguity of the external address pool. In particular, the NAT function must be configurable with contiguous or non-contiguous external IPv4 address ranges.
Likewise, one or multiple IP address pools may be configured for Destination NAT (dst-ip-address-pool).
Port numbers can be assigned by a NAT individually (that is, a single port is a assigned on a per session basis). Nevertheless, this port allocation scheme may not be optimal for logging purposes. Therefore, a NAT function should be able to assign port sets (e.g., [RFC7753]) to optimize the volume of the logging data (REQ-14 of [RFC6888]). Both features are supported in the NAT YANG data model.
When port set assignment is activated (i.e., port-allocation-type==port-range-allocation), the NAT can be provided with the size of the port set to be assigned (port-set-size).
Some NATs require to restrict the port numbers (e.g., Lightweight 4over6 [RFC7596], MAP-E [RFC7597]). Two schemes of port set assignments (port-set-restrict) are supported in this document:
A TCP/UDP mapping entry maintains an association between the following information:
An ICMP mapping entry maintains an association between the following information:
To cover TCP, UDP, and ICMP, the NAT YANG model assumes the following structure of a mapping entry:
In order to cover both NAT64 and NAT44 flavors in particular, the NAT mapping structure allows to include an IPv4 or an IPv6 address as an internal IP address. Remaining fields are common to both NAT schemes.
For example, the mapping that will be created by a NAT64 upon receipt of a TCP SYN from source address 2001:db8:aaaa::1 and source port number 25636 to destination IP address 2001:db8:1234::198.51.100.1 and destination port number 8080 is characterized as follows:
The mapping that will be created by a NAT44 upon receipt of an ICMP request from source address 198.51.100.1 and ICMP identifier (ID1) to destination IP address 198.51.100.11 is characterized as follows:
The mapping that will be created by a NAT64 upon receipt of an ICMP request from source address 2001:db8:aaaa::1 and ICMP identifier (ID1) to destination IP address 2001:db8:1234::198.51.100.1 is characterized as follows:
In order to comply with CGN deployments in particular, the data model allows limiting the number of external ports per subscriber (port-quota) and the amount of state memory allocated per mapping and per subscriber (mapping-limit and connection-limit). According to [RFC6888], the model allows for the following:
The model allows to specify the interface(s) on which the NAT function must be applied (external-interfaces). The model allows also to specify internal interfaces (interfaces-interfaces).
If no interface is provided, this assumes that the system is able to determine the external interface(s) on which the NAT will be applied. Typically, the WAN and LAN interfaces of a CPE is determined by the CPE.
The tree structure of the NAT data model is provided below:
module: ietf-nat
+--rw nat-module
+--rw nat-instances
+--rw nat-instance* [id]
+--rw id uint32
+--rw name? string
+--rw enable? boolean
+--ro nat-capabilities
| +--ro nat-flavor* identityref
| +--ro nat44-flavor* identityref
| +--ro restricted-port-support? boolean
| +--ro static-mapping-support? boolean
| +--ro port-randomization-support? boolean
| +--ro port-range-allocation-support? boolean
| +--ro port-preservation-suport? boolean
| +--ro port-parity-preservation-support? boolean
| +--ro address-roundrobin-support? boolean
| +--ro paired-address-pooling-support? boolean
| +--ro endpoint-independent-mapping-support? boolean
| +--ro address-dependent-mapping-support? boolean
| +--ro address-and-port-dependent-mapping-support? boolean
| +--ro endpoint-independent-filtering-support? boolean
| +--ro address-dependent-filtering? boolean
| +--ro address-and-port-dependent-filtering? boolean
+--rw internal-interfaces* [internal-interface]
| +--rw internal-interface if:interface-ref
+--rw external-interfaces* [external-interface]
| +--rw external-interface if:interface-ref
+--rw external-ip-address-pool* [pool-id]
| +--rw pool-id uint32
| +--rw external-ip-pool? inet:ipv4-prefix
+--rw port-set-restrict
| +--rw (port-type)?
| +--:(port-range)
| | +--rw start-port-number? inet:port-number
| | +--rw end-port-number? inet:port-number
| +--:(port-set-algo)
| +--rw psid-offset? uint8
| +--rw psid-len uint8
| +--rw psid uint16
+--rw dst-nat-enable? boolean
+--rw dst-ip-address-pool* [pool-id]
| +--rw pool-id uint32
| +--rw dst-in-ip-pool? inet:ip-prefix
| +--rw dst-out-ip-pool? inet:ip-prefix
+--rw nat64-prefixes* [nat64-prefix]
| +--rw nat64-prefix inet:ipv6-prefix
| +--rw destination-ipv4-prefix* [ipv4-prefix]
| +--rw ipv4-prefix inet:ipv4-prefix
+--rw clat-ipv6-prefixes* [clat-ipv6-prefix]
| +--rw clat-ipv6-prefix inet:ipv6-prefix
+--rw clat-ipv4-prefixes* [clat-ipv4-prefix]
| +--rw clat-ipv4-prefix inet:ipv4-prefix
+--rw nptv6-prefixes* [translation-id]
| +--rw translation-id uint32
| +--rw internal-ipv6-prefix? inet:ipv6-prefix
| +--rw external-ipv6-prefix? inet:ipv6-prefix
+--rw supported-transport-protocols* [transport-protocol-id]
| +--rw transport-protocol-id uint8
| +--rw transport-protocol-name? string
+--rw subscriber-mask-v6? uint8
+--rw subscriber-match* [sub-match-id]
| +--rw sub-match-id uint32
| +--rw sub-mask inet:ip-prefix
+--rw nat-pass-through* [nat-pass-through-id]
| +--rw nat-pass-through-id uint32
| +--rw nat-pass-through-pref? inet:ip-prefix
| +--rw nat-pass-through-port? inet:port-number
+--rw paired-address-pooling? boolean
+--rw nat-mapping-type? enumeration
+--rw nat-filtering-type? enumeration
+--rw port-quota* [quota-type]
| +--rw port-limit? uint16
| +--rw quota-type enumeration
+--rw port-allocation-type? enumeration
+--rw address-roundrobin-enable? boolean
+--rw port-set
| +--rw port-set-size? uint16
| +--rw port-set-timeout? uint32
+--rw udp-timeout? uint32
+--rw tcp-idle-timeout? uint32
+--rw tcp-trans-open-timeout? uint32
+--rw tcp-trans-close-timeout? uint32
+--rw tcp-in-syn-timeout? uint32
+--rw fragment-min-timeout? uint32
+--rw icmp-timeout? uint32
+--rw per-port-timeout* [port-number]
| +--rw port-number inet:port-number
| +--rw port-timeout inet:port-number
+--rw hold-down-timeout? uint32
+--rw hold-down-max? uint32
+--rw mapping-limit
| +--rw limit-per-subscriber? uint32
| +--rw limit-per-vrf? uint32
| +--rw limit-per-subnet? inet:ip-prefix
| +--rw limit-per-instance uint32
| +--rw limit-per-udp uint32
| +--rw limit-per-tcp uint32
| +--rw limit-per-icmp uint32
+--rw connection-limit
| +--rw limit-per-subscriber? uint32
| +--rw limit-per-vrf? uint32
| +--rw limit-per-subnet? inet:ip-prefix
| +--rw limit-per-instance uint32
| +--rw limit-per-udp uint32
| +--rw limit-per-tcp uint32
| +--rw limit-per-icmp uint32
+--rw algs* [alg-name]
| +--rw alg-name string
| +--rw alg-transport-protocol? uint32
| +--rw alg-transport-port? inet:port-number
| +--rw alg-status? boolean
+--rw all-algs-enable? boolean
+--rw logging-info
| +--rw logging-enable? boolean
| +--rw destination-address inet:ip-prefix
| +--rw destination-port inet:port-number
| +--rw (protocol)?
| +--:(syslog)
| | +--rw syslog? boolean
| +--:(ipfix)
| | +--rw ipfix? boolean
| +--:(ftp)
| +--rw ftp? boolean
+--rw notify-pool-usage
| +--rw pool-id? uint32
| +--rw notify-pool-hi-threshold percent
| +--rw notify-pool-low-threshold? percent
+--rw mapping-table
| +--rw mapping-entry* [index]
| +--rw index uint32
| +--rw type? enumeration
| +--rw transport-protocol? uint8
| +--rw internal-src-address? inet:ip-prefix
| +--rw internal-src-port
| | +--rw (port-type)?
| | +--:(single-port-number)
| | | +--rw single-port-number? inet:port-number
| | +--:(port-range)
| | +--rw start-port-number? inet:port-number
| | +--rw end-port-number? inet:port-number
| +--rw external-src-address? inet:ip-prefix
| +--rw external-src-port
| | +--rw (port-type)?
| | +--:(single-port-number)
| | | +--rw single-port-number? inet:port-number
| | +--:(port-range)
| | +--rw start-port-number? inet:port-number
| | +--rw end-port-number? inet:port-number
| +--rw internal-dst-address? inet:ip-prefix
| +--rw internal-dst-port
| | +--rw (port-type)?
| | +--:(single-port-number)
| | | +--rw single-port-number? inet:port-number
| | +--:(port-range)
| | +--rw start-port-number? inet:port-number
| | +--rw end-port-number? inet:port-number
| +--rw external-dst-address? inet:ip-prefix
| +--rw external-dst-port
| | +--rw (port-type)?
| | +--:(single-port-number)
| | | +--rw single-port-number? inet:port-number
| | +--:(port-range)
| | +--rw start-port-number? inet:port-number
| | +--rw end-port-number? inet:port-number
| +--rw lifetime? uint32
+--ro statistics
+--ro traffic-statistics
| +--ro sent-packet? yang:zero-based-counter64
| +--ro sent-byte? yang:zero-based-counter64
| +--ro rcvd-packet? yang:zero-based-counter64
| +--ro rcvd-byte? yang:zero-based-counter64
| +--ro dropped-packet? yang:zero-based-counter64
| +--ro dropped-byte? yang:zero-based-counter64
+--ro mapping-statistics
| +--ro total-mappings? uint32
| +--ro total-tcp-mappings? uint32
| +--ro total-udp-mappings? uint32
| +--ro total-icmp-mappings? uint32
+--ro pool-stats
+--ro pool-id? uint32
+--ro address-allocated? uint32
+--ro address-free? uint32
+--ro port-stats
+--ro ports-allocated? uint32
+--ro ports-free? uint32
notifications:
+---n nat-event
+--ro id? -> /nat-module/nat-instances/nat-instance/id
+--ro notify-pool-threshold percent
<CODE BEGINS> file "ietf-nat@2017-08-23.yang"
module ietf-nat {
namespace "urn:ietf:params:xml:ns:yang:ietf-nat";
//namespace to be assigned by IANA
prefix "nat";
import ietf-inet-types { prefix inet; }
import ietf-yang-types { prefix yang; }
import ietf-interfaces { prefix if; }
//import iana-if-type { prefix ianaift; }
organization "IETF OPSAWG Working Group";
contact
"Mohamed Boucadair <mohamed.boucadair@orange.com>
Senthil Sivakumar <ssenthil@cisco.com>
Chritsian Jacquenet <christian.jacquenet@orange.com>
Suresh Vinapamula <sureshk@juniper.net>
Qin Wu <bill.wu@huawei.com>";
description
"This module is a YANG module for NAT implementations
(including NAT44 and NAT64 flavors).
Copyright (c) 2017 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices.";
revision 2017-08-23 {
description "Comments from F. Baker about NPTv6.";
reference "-ietf-02";
}
revision 2017-08-21 {
description " Includes CLAT (Lee/Jordi).";
reference "-ietf-01";
}
revision 2017-08-03 {
description "Integrates comments from OPSAWG CFA.";
reference "-ietf-00";
}
revision 2017-07-03 {
description "Integrates comments from D. Wing and T. Zhou.";
reference "-07";
}
revision 2015-09-08 {
description "Fixes few YANG errors.";
reference "-02";
}
revision 2015-09-07 {
description "Completes the NAT64 model.";
reference "01";
}
revision 2015-08-29 {
description "Initial version.";
reference "00";
}
/*
* Definitions
*/
typedef percent {
type uint8 {
range "0 .. 100";
}
description
"Percentage";
}
/*
* Identities
*/
identity nat-type {
description
"Base identity for nat type.";
}
identity nat44 {
base nat:nat-type;
description
"Identity for traditional NAT support.";
reference
"RFC 3022.";
}
identity basic-nat {
//base nat:nat-type;
base nat:nat44;
description
"Identity for Basic NAT support.";
reference
"RFC 3022.";
}
identity napt {
//base nat:nat-type;
base nat:nat44;
description
"Identity for NAPT support.";
reference
"RFC 3022.";
}
identity restricted-nat {
//base nat:nat-type;
base nat:nat44;
description
"Identity for Port-Restricted NAT support.";
reference
"RFC 7596.";
}
identity dst-nat {
base nat:nat-type;
description
"Identity for Destination NAT support.";
}
identity nat64 {
base nat:nat-type;
description
"Identity for NAT64 support.";
reference
"RFC 6146.";
}
identity clat {
base nat:nat-type;
description
"Identity for CLAT support.";
reference
"RFC 6877.";
}
identity eam {
base nat:nat-type;
description
"Identity for EAM support.";
reference
"RFC 7757.";
}
identity nptv6 {
base nat:nat-type;
description
"Identity for NPTv6 support.";
reference
"RFC 6296.";
}
/*
* Grouping
*/
// Timers
grouping timeouts {
description
"Configure values of various timeouts.";
leaf udp-timeout {
type uint32;
units "seconds";
default 300;
description
"UDP inactivity timeout. That is the time a mapping
will stay active without packets traversing the NAT.";
reference
"RFC 4787.";
}
leaf tcp-idle-timeout {
type uint32;
units "seconds";
default 7440;
description
"TCP Idle timeout should be
2 hours and 4 minutes.";
reference
"RFC 5382.";
}
leaf tcp-trans-open-timeout {
type uint32;
units "seconds";
default 240;
description
"The value of the transitory open connection
idle-timeout.
Section 2.1 of [RFC7857] clarifies that a NAT
should provide different configurable
parameters for configuring the open and
closing idle timeouts.
To accommodate deployments that consider
a partially open timeout of 4 minutes as being
excessive from a security standpoint, a NAT may
allow the configured timeout to be less than
4 minutes.
However, a minimum default transitory connection
idle-timeout of 4 minutes is recommended.";
reference
"RFC 7857.";
}
leaf tcp-trans-close-timeout {
type uint32;
units "seconds";
default 240;
description
"The value of the transitory close connection
idle-timeout.
Section 2.1 of [RFC7857] clarifies that a NAT
should provide different configurable
parameters for configuring the open and
closing idle timeouts.";
reference
"RFC 7857.";
}
leaf tcp-in-syn-timeout {
type uint32;
units "seconds";
default 6;
description
"A NAT must not respond to an unsolicited
inbound SYN packet for at least 6 seconds
after the packet is received. If during
this interval the NAT receives and translates
an outbound SYN for the connection the NAT
must silently drop the original unsolicited
inbound SYN packet.";
reference
"RFC 5382.";
}
leaf fragment-min-timeout {
type uint32;
units "seconds";
default 2;
description
"As long as the NAT has available resources,
the NAT allows the fragments to arrive
over fragment-min-timeout interval.
The default value is inspired from RFC6146.";
}
leaf icmp-timeout {
type uint32;
units "seconds";
default 60;
description
"An ICMP Query session timer must not expire
in less than 60 seconds. It is recommended
that the ICMP Query session timer be made
configurable";
reference
"RFC 5508.";
}
list per-port-timeout {
key port-number;
description
"Some NATs are configurable with short timeouts
for some ports, e.g., as 10 seconds on
port 53 (DNS) and NTP (123) and longer timeouts
on other ports.";
leaf port-number {
type inet:port-number;
description
"A port number.";
}
leaf port-timeout {
type inet:port-number;
mandatory true;
description
"Timeout for this port";
}
}
leaf hold-down-timeout {
type uint32;
units "seconds";
default 120;
description
"Hold down timer. Ports in the
hold down pool are not reassigned until
this timer expires.
The length of time and the maximum
number of ports in this state must be
configurable by the administrator
[RFC6888]. This is necessary in order
to prevent collisions between old
and new mappings and sessions. It ensures
that all established sessions are broken
instead of redirected to a different peer.";
reference
"REQ#8 of RFC 6888.";
}
leaf hold-down-max {
type uint32;
description
"Maximum ports in the Hold down timer pool.
Ports in the hold down pool are not reassigned
until hold-down-timeout expires.
The length of time and the maximum
number of ports in this state must be
configurable by the administrator
[RFC6888]. This is necessary in order
to prevent collisions between old
and new mappings and sessions. It ensures
that all established sessions are broken
instead of redirected to a different peer.";
reference
"REQ#8 of RFC 6888.";
}
}
// Set of ports
grouping port-set {
description
"Indicates a set of ports.
It may be a simple port range, or use the PSID algorithm
to represent a range of transport layer
ports which will be used by a NAPT.";
choice port-type {
default port-range;
description
"Port type: port-range or port-set-algo.";
case port-range {
leaf start-port-number {
type inet:port-number;
description
"Begining of the port range.";
reference
"Section 3.2.9 of RFC 8045.";
}
leaf end-port-number {
type inet:port-number;
description
"End of the port range.";
reference
"Section 3.2.10 of RFC 8045.";
}
}
case port-set-algo {
leaf psid-offset {
type uint8 {
range 0..16;
}
description
"The number of offset bits. In Lightweight 4over6,
the default value is 0 for assigning one contiguous
port range. In MAP-E/T, the default value is 6,
which excludes system ports by default and assigns
port ranges distributed across the entire port
space.";
}
leaf psid-len {
type uint8 {
range 0..15;
}
mandatory true;
description
"The length of PSID, representing the sharing
ratio for an IPv4 address.";
}
leaf psid {
type uint16;
mandatory true;
description
"Port Set Identifier (PSID) value, which
identifies a set of ports algorithmically.";
}
}
}
}
// port numbers: single or port-range
grouping port-number {
description
"Individual port or a range of ports.";
choice port-type {
default single-port-number;
description
"Port type: single or port-range.";
case single-port-number {
leaf single-port-number {
type inet:port-number;
description
"Used for single port numbers.";
}
}
case port-range {
leaf start-port-number {
type inet:port-number;
description
"Begining of the port range.";
reference
"Section 3.2.9 of RFC 8045.";
}
leaf end-port-number {
type inet:port-number;
description
"End of the port range.";
reference
"Section 3.2.10 of RFC 8045.";
}
}
}
}
// Mapping Entry
grouping mapping-entry {
description
"NAT mapping entry.";
leaf index {
type uint32;
description
"A unique identifier of a mapping entry.";
}
leaf type {
type enumeration {
enum "static" {
description
"The mapping entry is manually
configured.";
}
enum "dynamic-explicit" {
description
"This mapping is created by an
outgoing packet.";
}
enum "dynamic-implicit" {
description
"This mapping is created by an
explicit dynamic message.";
}
}
description
"Indicates the type of a mapping entry. E.g.,
a mapping can be: static, implicit dynamic
or explicit dynamic.";
}
leaf transport-protocol {
type uint8;
description
"Upper-layer protocol associated with this mapping.
Values are taken from the IANA protocol registry.
For example, this field contains 6 (TCP) for a TCP
mapping or 17 (UDP) for a UDP mapping. No transport
protocol is indicated if a mapping applies for any
protocol.";
}
leaf internal-src-address {
type inet:ip-prefix;
description
"Corresponds to the source IPv4/IPv6 address/prefix
of the packet received on an internal
interface.";
}
container internal-src-port {
description
"Corresponds to the source port of the
packet received on an internal interface.
It is used also to carry the internal
source ICMP identifier.";
uses port-number;
}
leaf external-src-address {
type inet:ip-prefix;
description
"Source IP address/prefix of the packet sent
on an external interface of the NAT.";
}
container external-src-port {
description
"Source port of the packet sent
on an external interafce of the NAT.
It is used also to carry the external
source ICMP identifier.";
uses port-number;
}
leaf internal-dst-address {
type inet:ip-prefix;
description
"Corresponds to the destination IP address/prefix
of the packet received on an internal interface
of the NAT.
For example, some NAT implementations support
the translation of both source and destination
addresses and ports, sometimes referred to
as 'Twice NAT'.";
}
container internal-dst-port {
description
"Corresponds to the destination port of the
IP packet received on the internal interface.
It is used also to carry the internal
destination ICMP identifier.";
uses port-number;
}
leaf external-dst-address {
type inet:ip-prefix;
description
"Corresponds to the destination IP address/prefix
of the packet sent on an external interface
of the NAT.";
}
container external-dst-port {
description
"Corresponds to the destination port number of
the packet sent on the external interface
of the NAT.
It is used also to carry the external
destination ICMP identifier.";
uses port-number;
}
leaf lifetime {
type uint32;
//mandatory true;
description
"When specified, it tracks the connection that is
fully-formed (e.g., once the 3WHS TCP is completed)
or the duration for maintaining an explicit mapping
alive. Static mappings may not be associated with a
lifetime. If no lifetime is associated with a
static mapping, an explicit action is requried to
remove that mapping.";
}
}
grouping nat-parameters {
description
"NAT parameters for a given instance";
list external-ip-address-pool {
key pool-id;
description
"Pool of external IP addresses used to
service internal hosts.
Both contiguous and non-contiguous pools
can be configured for NAT purposes.";
leaf pool-id {
type uint32;
description
"An identifier of the address pool.";
}
leaf external-ip-pool {
type inet:ipv4-prefix;
description
"An IPv4 prefix used for NAT purposes.";
}
}
container port-set-restrict {
when "../nat-capabilities/restricted-port-support = 'true'";
description
"Configures contiguous and non-contiguous port ranges.";
uses port-set;
}
leaf dst-nat-enable {
type boolean;
default false;
description
"Enable/Disable destination NAT.
A NAT44 may be configured to enable
Destination NAT, too.";
}
list dst-ip-address-pool {
//if-feature dst-nat;
when "../nat-capabilities/nat-flavor = 'dst-nat' ";
key pool-id;
description
"Pool of IP addresses used for destination NAT.";
leaf pool-id {
type uint32;
description
"An identifier of the address pool.";
}
leaf dst-in-ip-pool {
type inet:ip-prefix;
description
"Internal IP prefix/address";
}
leaf dst-out-ip-pool {
type inet:ip-prefix;
description
"IP address/prefix used for destination NAT.";
}
}
list nat64-prefixes {
when "../nat-capabilities/nat-flavor = 'nat64' " +
" or ../nat-capabilities/nat-flavor = 'clat'";
key nat64-prefix;
description
"Provides one or a list of NAT64 prefixes
with or without a list of destination IPv4 prefixes.
Destination-based Pref64::/n is discussed in
Section 5.1 of [RFC7050]). For example:
192.0.2.0/24 is mapped to 2001:db8:122:300::/56.
198.51.100.0/24 is mapped to 2001:db8:122::/48.";
reference
"Section 5.1 of RFC7050.";
leaf nat64-prefix {
type inet:ipv6-prefix;
//default "64:ff9b::/96";
description
"A NAT64 prefix. Can be NSP or a Well-Known
Prefix (WKP).";
reference
"RFC 6052.";
}
list destination-ipv4-prefix {
key ipv4-prefix;
description
"An IPv4 prefix/address.";
leaf ipv4-prefix {
type inet:ipv4-prefix;
description
"An IPv4 address/prefix.";
}
}
}
list clat-ipv6-prefixes {
when "../nat-capabilities/nat-flavor = 'clat' ";
key clat-ipv6-prefix;
description
"464XLAT double translation treatment is
stateless when a dedicated /64 is available
for translation on the CLAT. Otherwise, the
CLAT will have both stateful and stateless
since it requires NAT44 from the LAN to
a single IPv4 address and then stateless
translation to a single IPv6 address.";
reference
"RFC 6877.";
leaf clat-ipv6-prefix {
type inet:ipv6-prefix;
description
"An IPv6 prefix used for CLAT.";
}
}
list clat-ipv4-prefixes {
when "../nat-capabilities/nat-flavor = 'clat'";
key clat-ipv4-prefix;
description
"Pool of IPv4 addresses used for CLAT.
192.0.0.0/29 is the IPv4 service continuity
prefix.";
reference
"RFC 7335.";
leaf clat-ipv4-prefix {
type inet:ipv4-prefix;
description
"464XLAT double translation treatment is
stateless when a dedicated /64 is available
for translation on the CLAT. Otherwise, the
CLAT will have both stateful and stateless
since it requires NAT44 from the LAN to
a single IPv4 address and then stateless
translation to a single IPv6 address.
The CLAT performs NAT44 for all IPv4 LAN
packets so that all the LAN-originated IPv4
packets appear from a single IPv4 address
and are then statelessly translated to one
interface IPv6 address that is claimed by
the CLAT.
An IPv4 address from this pool is also
provided to an application that makes
use of literals.";
reference
"RFC 6877.";
}
}
list nptv6-prefixes {
when "../nat-capabilities/nat-flavor = 'nptv6' ";
key translation-id;
description
"Provides one or a list of (internal IPv6 prefix,
external IPv6 prefix) required for NPTv6.
In its simplest form, NPTv6 interconnects two network
links, one of which is an 'internal' network link
attachedto a leaf network within a single
administrative domain and the other of which is an
'external' network with connectivity to the global
Internet.";
reference
"RFC 6296.";
leaf translation-id {
type uint32;
description
"An identifier of the NPTv6 prefixs.";
}
leaf internal-ipv6-prefix {
type inet:ipv6-prefix;
description
"An IPv6 prefix used by an internal interface
of NPTv6.";
reference
"RFC 6296.";
}
leaf external-ipv6-prefix {
type inet:ipv6-prefix;
description
"An IPv6 prefix used by the external interface
of NPTv6.";
reference
"RFC 6296.";
}
}
list supported-transport-protocols {
key transport-protocol-id;
description
"Supported transport protocols.
TCP and UDP are supported by default.";
leaf transport-protocol-id {
type uint8;
mandatory true;
description
"Upper-layer protocol associated with this mapping.
Values are taken from the IANA protocol registry.
For example, this field contains 6 (TCP) for a TCP
mapping or 17 (UDP) for a UDP mapping.";
}
leaf transport-protocol-name {
type string;
description
"For example, TCP, UDP, DCCP, and SCTP.";
}
}
leaf subscriber-mask-v6 {
type uint8 {
range "0 .. 128";
}
description
"The subscriber-mask is an integer that indicates
the length of significant bits to be applied on
the source IP address (internal side) to
unambiguously identify a CPE.
Subscriber-mask is a system-wide configuration
parameter that is used to enforce generic
per-subscriber policies (e.g., port-quota).
The enforcement of these generic policies does not
require the configuration of every subscriber's
prefix.
Example: suppose the 2001:db8:100:100::/56 prefix
is assigned to a NAT64 serviced CPE. Suppose also
that 2001:db8:100:100::1 is the IPv6 address used
by the client that resides in that CPE. When the
NAT64 receives a packet from this client,
it applies the subscriber-mask (e.g., 56) on
the source IPv6 address to compute the associated
prefix for this client (2001:db8:100:100::/56).
Then, the NAT64 enforces policies based on that
prefix (2001:db8:100:100::/56), not on the exact
source IPv6 address.";
}
list subscriber-match {
key sub-match-id;
description
"IP prefix match.";
leaf sub-match-id {
type uint32;
description
"An identifier of the subscriber masck.";
}
leaf sub-mask {
type inet:ip-prefix;
mandatory true;
description
"The IP address subnets that match
should be translated. E.g., all addresses
that belong to the 192.0.2.0/24 prefix must
be processed by the NAT.";
}
}
list nat-pass-through {
key nat-pass-through-id;
description
"IP prefix NAT pass through.";
leaf nat-pass-through-id {
type uint32;
description
"An identifier of the IP prefix pass
through.";
}
leaf nat-pass-through-pref {
type inet:ip-prefix;
description
"The IP address subnets that match
should not be translated. According to
REQ#6 of RFC6888, it must be possible
to administratively turn off translation
for specific destination addresses
and/or ports.";
}
leaf nat-pass-through-port {
type inet:port-number;
description
"The IP address subnets that match
should not be translated. According to
REQ#6 of RFC6888, it must be possible to
administratively turn off translation
for specific destination addresses
and/or ports.";
}
}
leaf paired-address-pooling {
type boolean;
default true;
description
"Paired address pooling informs the NAT
that all the flows from an internal IP
address must be assigned the same external
address.";
reference
"RFC 4007.";
}
leaf nat-mapping-type {
type enumeration {
enum "eim" {
description
"endpoint-independent-mapping.";
reference
"Section 4 of RFC 4787.";
}
enum "adm" {
description
"address-dependent-mapping.";
reference
"Section 4 of RFC 4787.";
}
enum "edm" {
description
"address-and-port-dependent-mapping.";
reference
"Section 4 of RFC 4787.";
}
}
description
"Indicates the type of a NAT mapping.";
}
leaf nat-filtering-type {
type enumeration {
enum "eif" {
description
"endpoint-independent- filtering.";
reference
"Section 5 of RFC 4787.";
}
enum "adf" {
description
"address-dependent-filtering.";
reference
"Section 5 of RFC 4787.";
}
enum "edf" {
description
"address-and-port-dependent-filtering";
reference
"Section 5 of RFC 4787.";
}
}
description
"Indicates the type of a NAT filtering.";
}
list port-quota {
when "../nat-capabilities/nat44-flavor = "+
"'napt' or "+
"../nat-capabilities/nat-flavor = "+
"'nat64'";
key quota-type;
description
"Configures a port quota to be assigned per
subscriber. It corresponds to the maximum
number of ports to be used by a subscriber.";
leaf port-limit {
type uint16;
description
"Configures a port quota to be assigned per
subscriber. It corresponds to the maximum
number of ports to be used by a subscriber.";
reference
"REQ-4 of RFC 6888.";
}
leaf quota-type {
type enumeration {
enum "all" {
description
"The limit applies to all protocols.";
reference
"REQ-4 of RFC 6888.";
}
enum "tcp" {
description
"TCP quota.";
reference
"REQ-4 of RFC 6888.";
}
enum "udp" {
description
"UDP quota.";
reference
"REQ-4 of RFC 6888.";
}
enum "icmp" {
description
"ICMP quota.";
reference
"REQ-4 of RFC 6888.";
}
}
description
"Indicates whether the port quota applies to
all protocols or to a specific transport.";
}
}
leaf port-allocation-type {
type enumeration {
enum "random" {
description
"Port randomization is enabled.";
}
enum "port-preservation" {
description
"Indicates whether the NAT should
preserve the internal port number.";
}
enum "port-parity-preservation" {
description
"Indicates whether the NAT should
preserve the port parity of the
internal port number.";
}
enum "port-range-allocation" {
description
"Indicates whether the NAT assigns a
range of ports for an internal host.";
}
}
description
"Indicates the type of a port allocation.";
}
leaf address-roundrobin-enable {
type boolean;
description
"Enable/disable address allocation
round robin.";
}
container port-set {
when "../port-allocation-type='port-range-allocation'";
description
"Manages port-set assignments.";
leaf port-set-size {
type uint16;
description
"Indicates the size of assigned port
sets.";
}
leaf port-set-timeout {
type uint32;
description
"Inactivty timeout for port sets.";
}
}
uses timeouts;
container mapping-limit {
description
"Information about the configuration parameters that
limits the mappings based upon various criteria.";
leaf limit-per-subscriber {
type uint32;
description
"Maximum number of NAT mappings per
subscriber.";
}
leaf limit-per-vrf {
type uint32;
description
"Maximum number of NAT mappings per
VLAN/VRF.";
}
leaf limit-per-subnet {
type inet:ip-prefix;
description
"Maximum number of NAT mappings per
subnet.";
}
leaf limit-per-instance {
type uint32;
mandatory true;
description
"Maximum number of NAT mappings per
instance.";
}
leaf limit-per-udp {
type uint32;
mandatory true;
description
"Maximum number of UDP NAT mappings per
subscriber.";
}
leaf limit-per-tcp {
type uint32;
mandatory true;
description
"Maximum number of TCP NAT mappings per
subscriber.";
}
leaf limit-per-icmp {
type uint32;
mandatory true;
description
"Maximum number of ICMP NAT mappings per
subscriber.";
}
}
container connection-limit {
description
"Information about the configuration parameters that
rate limit the translation based upon various
criteria.";
leaf limit-per-subscriber {
type uint32;
description
"Rate-limit the number of new mappings
and sessions per subscriber.";
}
leaf limit-per-vrf {
type uint32;
description
"Rate-limit the number of new mappings
and sessions per VLAN/VRF.";
}
leaf limit-per-subnet {
type inet:ip-prefix;
description
"Rate-limit the number of new mappings
and sessions per subnet.";
}
leaf limit-per-instance {
type uint32;
mandatory true;
description
"Rate-limit the number of new mappings
and sessions per instance.";
}
leaf limit-per-udp {
type uint32;
mandatory true;
description
"Rate-limit the number of new UDP mappings
and sessions per subscriber.";
}
leaf limit-per-tcp {
type uint32;
mandatory true;
description
"Rate-limit the number of new TCP mappings
and sessions per subscriber.";
}
leaf limit-per-icmp {
type uint32;
mandatory true;
description
"Rate-limit the number of new ICMP mappings
and sessions per subscriber.";
}
}
list algs {
key alg-name;
description
"ALG-related features.";
leaf alg-name {
type string;
description
"The name of the ALG";
}
leaf alg-transport-protocol {
type uint32;
description
"The transport protocol used by the ALG.";
}
leaf alg-transport-port {
type inet:port-number;
description
"The port number used by the ALG.";
}
leaf alg-status {
type boolean;
description
"Enable/disable the ALG.";
}
}
leaf all-algs-enable {
type boolean;
description
"Enable/disable all ALGs.";
}
container logging-info {
description
"Information about logging NAT events";
leaf logging-enable {
type boolean;
description
"Enable logging features as per Section 2.3
of [RFC6908].";
}
leaf destination-address {
type inet:ip-prefix;
mandatory true;
description
"Address of the collector that receives
the logs";
}
leaf destination-port {
type inet:port-number;
mandatory true;
description
"Destination port of the collector.";
}
choice protocol {
description
"Enable the protocol to be used for
the retrieval of logging entries.";
case syslog {
leaf syslog {
type boolean;
description
"If SYSLOG is in use.";
}
}
case ipfix {
leaf ipfix {
type boolean;
description
"If IPFIX is in use.";
}
}
case ftp {
leaf ftp {
type boolean;
description
"If FTP is in use.";
}
}
}
}
container notify-pool-usage {
description
"Notification of pool usage when certain criteria
are met.";
leaf pool-id {
type uint32;
description
"Pool-ID for which the notification
criteria is defined";
}
leaf notify-pool-hi-threshold {
type percent;
mandatory true;
description
"Notification must be generated when the
defined high threshold is reached.
For example, if a notification is
required when the pool utilization reaches
90%, this configuration parameter must
be set to 90%.";
}
leaf notify-pool-low-threshold {
type percent;
description
"Notification must be generated when the defined
low threshold is reached.
For example, if a notification is required when
the pool utilization reaches below 10%,
this configuration parameter must be set to
10%.";
}
}
} //nat-parameters group
container nat-module {
description
"NAT";
container nat-instances {
description
"NAT instances";
list nat-instance {
key "id";
description
"A NAT instance.";
leaf id {
type uint32;
description
"NAT instance identifier.";
reference
"RFC 7659.";
}
leaf name {
type string;
description
"A name associated with the NAT instance.";
}
leaf enable {
type boolean;
description
"Status of the the NAT instance.";
}
container nat-capabilities {
config false;
description
"NAT capabilities";
leaf-list nat-flavor {
type identityref {
base nat-type;
}
description
"Type of NAT.";
}
leaf-list nat44-flavor {
when "../nat-flavor = 'nat44'";
type identityref {
base nat44;
}
description
"Type of NAT44: Basic NAT or NAPT.";
}
leaf restricted-port-support {
type boolean;
description
"Indicates source port NAT restriction
support.";
}
leaf static-mapping-support {
type boolean;
description
"Indicates whether static mappings are
supported.";
}
leaf port-randomization-support {
type boolean;
description
"Indicates whether port randomization is
supported.";
}
leaf port-range-allocation-support {
type boolean;
description
"Indicates whether port range
allocation is supported.";
}
leaf port-preservation-suport {
type boolean;
description
"Indicates whether port preservation
is supported.";
}
leaf port-parity-preservation-support {
type boolean;
description
"Indicates whether port parity
preservation is supported.";
}
leaf address-roundrobin-support {
type boolean;
description
"Indicates whether address allocation
round robin is supported.";
}
leaf paired-address-pooling-support {
type boolean;
description
"Indicates whether paired-address-pooling is
supported";
}
leaf endpoint-independent-mapping-support {
type boolean;
description
"Indicates whether endpoint-independent-
mapping in Section 4 of RFC 4787 is
supported.";
}
leaf address-dependent-mapping-support {
type boolean;
description
"Indicates whether address-dependent-
mapping is supported.";
}
leaf address-and-port-dependent-mapping-support
{
type boolean;
description
"Indicates whether address-and-port-
dependent-mapping is supported.";
}
leaf endpoint-independent-filtering-support
{
type boolean;
description
"Indicates whether endpoint-independent
-filtering is supported.";
}
leaf address-dependent-filtering {
type boolean;
description
"Indicates whether address-dependent
-filtering is supported.";
}
leaf address-and-port-dependent-filtering {
type boolean;
description
"Indicates whether address-and-port
-dependent is supported.";
}
}
list internal-interfaces {
key internal-interface;
description
"List of internal interfaces.";
leaf internal-interface {
type if:interface-ref;
description
"Name of an internal interface.";
}
}
list external-interfaces {
key external-interface;
description
"List of external interfaces.";
leaf external-interface {
type if:interface-ref;
description
"Name of an external interface.";
}
}
uses nat-parameters;
container mapping-table {
when "../nat-capabilities/nat-flavor = "+
"'nat44' or "+
"../nat-capabilities/nat-flavor = "+
"'nat64'or "+
"../nat-capabilities/nat-flavor = "+
"'clat'or "+
"../nat-capabilities/nat-flavor = 'dst-nat'";
description
"NAT mapping table. Applicable for functions
which maintains static and/or dynamic mappings,
such as NAT44, Destination NAT, NAT64, CLAT,
or EAM.";
list mapping-entry {
key "index";
description
"NAT mapping entry.";
uses mapping-entry;
}
}
container statistics {
config false;
description
"Statistics related to the NAT instance.";
container traffic-statistics {
description
"Generic traffic statistics.";
leaf sent-packet {
type yang:zero-based-counter64;
description
"Number of packets sent.";
}
leaf sent-byte {
type yang:zero-based-counter64;
description
"Counter for sent traffic in bytes.";
}
leaf rcvd-packet {
type yang:zero-based-counter64;
description
"Number of received packets.";
}
leaf rcvd-byte {
type yang:zero-based-counter64;
description
"Counter for received traffic
in bytes.";
}
leaf dropped-packet {
type yang:zero-based-counter64;
description
"Number of dropped packets.";
}
leaf dropped-byte {
type yang:zero-based-counter64;
description
"Counter for dropped traffic in
bytes.";
}
}
container mapping-statistics {
when "../../nat-capabilities/nat-flavor = "+
"'nat44' or "+
"../../nat-capabilities/nat-flavor = "+
"'nat64'or "+
"../../nat-capabilities/nat-flavor = 'dst-nat'";
description
"Mapping statistics.";
leaf total-mappings {
type uint32;
description
"Total number of NAT mappings present
at a given time. This variable includes
all the static and dynamic mappings.";
}
leaf total-tcp-mappings {
type uint32;
description
"Total number of TCP mappings present
at a given time.";
}
leaf total-udp-mappings {
type uint32;
description
"Total number of UDP mappings present
at a given time.";
}
leaf total-icmp-mappings {
type uint32;
description
"Total number of ICMP mappings present
at a given time.";
}
}
container pool-stats {
when "../../nat-capabilities/nat-flavor = "+
"'nat44' or "+
"../../nat-capabilities/nat-flavor = "+
"'nat64'";
description
"Statistics related to address/prefix
pool usage";
leaf pool-id {
type uint32;
description
"Unique Identifier that represents
a pool of addresses/prefixes.";
}
leaf address-allocated {
type uint32;
description
"Number of allocated addresses in
the pool";
}
leaf address-free {
type uint32;
description
"Number of unallocated addresses in
the pool at a given time.The sum of
unallocated and allocated
addresses is the total number of
addresses of the pool.";
}
container port-stats {
description
"Statistics related to port
usage.";
leaf ports-allocated {
type uint32;
description
"Number of allocated ports
in the pool.";
}
leaf ports-free {
type uint32;
description
"Number of unallocated addresses
in the pool.";
}
}
}
} //statistics
}
}
}
/*
* Notifications
*/
notification nat-event {
description
"Notifications must be generated when the defined
high/low threshold is reached. Related
configuration parameters must be provided to
trigger the notifications.";
leaf id {
type leafref {
path
"/nat-module/nat-instances/"
+ "nat-instance/id";
}
description
"NAT instance ID.";
}
leaf notify-pool-threshold {
type percent;
mandatory true;
description
"A treshhold has been fired.";
}
}
}
<CODE ENDS>
The YANG module defined in this memo is designed to be accessed via the NETCONF protocol [RFC6241]. The lowest NETCONF layer is the secure transport layer and the support of SSH is mandatory to implement secure transport [RFC6242]. The NETCONF access control model [RFC6536] provides means to restrict access by some users to a pre-configured subset of all available NETCONF protocol operations and data.
All data nodes defined in the YANG module which can be created, modified and deleted (i.e., config true, which is the default). These data nodes are considered sensitive. Write operations (e.g., edit-config) applied to these data nodes without proper protection can negatively affect network operations.
URI: urn:ietf:params:xml:ns:yang:ietf-nat
Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace.
name: ietf-nat
namespace: urn:ietf:params:xml:ns:yang:ietf-nat
prefix: nat
reference: RFC XXXX
This document requests IANA to register the following URI in the "IETF XML Registry" [RFC3688]: [RFC6020].
Many thanks to Dan Wing and Tianran Zhou for the review.
Thanks to Juergen Schoenwaelder for the comments on the YANG structure and the suggestion to use NMDA.
Thanks to Lee Howard and Jordi Palet for the CLAT comments and to Fred Baker for the NPTv6 comments.
Special thanks to Maros Marsalek and Marek Gradzki for sharing their comments based on the FD.io implementation.
This section provides a non-exhaustive set of examples to illustrate the use of the NAT YANG module.
Traditional NAT44 is a Basic NAT44 or NAPT that is used to share the same IPv4 address among hosts that are owned by the same subscriber. This is typically the NAT that is embedded in CPE devices.
This NAT is usually provided with one single external IPv4 address; disambiguating connections is achieved by rewriting the source port number. The XML snippet to configure the external IPv4 address in such case together with a mapping entry is depicted below:
<nat-instances>
<nat-instance>
<id>1</id>
<name>NAT_Subscriber_A</name>
....
<external-ip-address-pool>
<pool-id>1</pool-id>
<external-ip-pool>
192.0.2.1
</external-ip-pool>
</external-ip-address-pool>
....
<mapping-table>
....
<external-src-address>
192.0.2.1
</external-src-address>
....
<mapping-table>
</nat-instance>
</nat-instances>
The following shows the XML excerpt depicting a dynamic UDP mapping entry maintained by a traditional NAT44. In reference to this example, the UDP packet received with a source IPv4 address (192.0.2.1) and source port number (1568) is translated into a UDP packet having a source IPv4 address (198.51.100.1) and source port (15000). The lifetime of this mapping is 300 seconds.
<mapping-entry>
<index>15</index>
<type>
dynamic-explicit
</type>
<transport-protocol>
17
</transport-protocol>
<internal-src-address>
192.0.2.1
</internal-dst-address>
<internal-src-port>
<single-port-number>
1568
</single-port-number>
</internal-dst-port>
<external-dst-address>
198.51.100.1
</external-dst-address>
<external-dst-port>
<single-port-number>
15000
</single-port-number>
</external-dst-port>
<lifetime>
300
</lifetime>
</mapping-entry>
The following XML snippet shows the example of the capabilities supported by a CGN as retrieved using NETCONF.
<nat-capabilities
<nat-flavor>
nat44
</nat44-flavor>
<restricted-port-support>
false
</restricted-port-support>
<static-mapping-support>
true
</static-mapping-support>
<port-randomization-support>
true
</port-randomization-support>
<port-range-allocation-support>
true
</port-range-allocation-support>
<port-preservation-suport>
true
</port-preservation-suport>
<port-parity-preservation-support>
false
</port-parity-preservation-support>
<address-roundrobin-support>
true
</address-roundrobin-support>
<paired-address-pooling-support>
true
</paired-address-pooling-support>
<endpoint-independent-mapping-support>
true
</endpoint-independent-mapping-support>
<address-dependent-mapping-support>
false
</address-dependent-mapping-support>
<address-and-port-dependent-mapping-support>
false
</address-and-port-dependent-mapping-support>
<endpoint-independent-filtering-support>
true
</endpoint-independent-filtering-support>
<address-dependent-filtering>
false
</address-dependent-filtering>
<address-and-port-dependent-filtering>
false
</address-and-port-dependent-filtering>
</nat-capabilities>
<nat-instances>
<nat-instance>
<id>1</id>
<name>myCGN</name>
....
<external-ip-address-pool>
<pool-id>1</pool-id>
<external-ip-pool>
192.0.2.0/24
</external-ip-pool>
</external-ip-address-pool>
<port-quota>
<port-limit>
1024
</port-limit>
<quota-type >
all
</quota-type >
</port-quota>
<port-allocation-type>
port-range-allocation
</port-allocation-type>
<port-set>
<port-set-size>
256
</port-set-size>
</port-set>
....
</nat-instance>
</nat-instances>
<nat-instances>
<nat-instance>
<id>1</id>
<name>myotherCGN</name>
....
<external-ip-address-pool>
<pool-id>1</pool-id>
<external-ip-pool>
192.0.2.0/24
</external-ip-pool>
</external-ip-address-pool>
<port-quota>
<port-limit>
1024
</port-limit>
<quota-type >
all
</quota-type >
</port-quota>
<port-allocation-type>
port-range-allocation
</port-allocation-type>
<port-set>
<port-set-size>
1024
</port-set-size>
....
</port-set>
....
</nat-instance>
</nat-instances>
Figure 1 illustrates an example of the CGN pass-through feature.
X1:x1 X1':x1' X2:x2
+---+from X1:x1 +---+from X1:x1 +---+
| C | to X2:x2 | | to X2:x2 | S |
| l |>>>>>>>>>>>>| C |>>>>>>>>>>>>>>| e |
| i | | G | | r |
| e |<<<<<<<<<<<<| N |<<<<<<<<<<<<<<| v |
| n |from X2:x2 | |from X2:x2 | e |
| t | to X1:x1 | | to X1:x1 | r |
+---+ +---+ +---+
Figure 1: CGN Pass-Through
<nat-pass-through>
...
<nat-pass-through-pref>192.0.2.25</nat-pass-through-pref>
...
</nat-pass-through>
Let's consider the example of a NAT64 that should use 2001:db8:122:300::/56 to perform IPv6 address synthesis [RFC6052]. The XML snippet to configure the NAT64 prefix in such case is depicted below:
<nat64-prefixes>
<nat64-prefix>
2001:db8:122:300::/56
</nat64-prefix>
</nat64-prefixes>
Let's now consider the example of a NAT64 that should use 2001:db8:122::/48 to perform IPv6 address synthesis [RFC6052] only if the destination address matches 198.51.100.0/24. The XML snippet to configure the NAT64 prefix in such case is shown below:
<nat64-prefixes>
<nat64-prefix>
2001:db8:122::/48
</nat64-prefix>
<destination-ipv4-prefix>
<ipv4-prefix>
198.51.100.0/24
</ipv4-prefix>
</destination-ipv4-prefix>
</nat64-prefixes>
As specified in [RFC7757], an EAM consists of an IPv4 prefix and an IPv6 prefix. Let's consider the set of EAM examples in Figure 2.
+---+----------------+----------------------+
| # | IPv4 Prefix | IPv6 Prefix |
+---+----------------+----------------------+
| 1 | 192.0.2.1 | 2001:db8:aaaa:: |
| 2 | 192.0.2.2/32 | 2001:db8:bbbb::b/128 |
| 3 | 192.0.2.16/28 | 2001:db8:cccc::/124 |
| 4 | 192.0.2.128/26 | 2001:db8:dddd::/64 |
| 5 | 192.0.2.192/29 | 2001:db8:eeee:8::/62 |
| 6 | 192.0.2.224/31 | 64:ff9b::/127 |
+---+----------------+----------------------+
Figure 2: EAM Examples (RFC7757)
<mapping-table>
<mapping-entry>
<index>1</index>
<type>static</type>
<internal-dst-address>
192.0.2.1
</internal-dst-address>
<external-dst-address>
2001:db8:aaaa::
</external-dst-address>
</mapping-entry>
<mapping-entry>
<index>2</index>
<type>static</type>
<internal-dst-address>
192.0.2.2/32
</internal-dst-address>
<external-dst-address>
2001:db8:bbbb::b/128
</external-dst-address>
</mapping-entry>
<mapping-entry>
<index>3</index>
<type>static</type>
<internal-dst-address>
192.0.2.16/28
</internal-dst-address>
<external-dst-address>
2001:db8:cccc::/124
</external-dst-address>
</mapping-entry>
<mapping-entry>
<index>4</index>
<type>static</type>
<internal-dst-address>
192.0.2.128/26
</internal-dst-address>
<external-dst-address>
2001:db8:dddd::/64
</external-dst-address>
</mapping-entry>
<mapping-entry>
<index>5</index>
<type>static</type>
<internal-dst-address>
192.0.2.192/29
</internal-dst-address>
<external-dst-address>
2001:db8:eeee:8::/62
</external-dst-address>
</mapping-entry>
<mapping-entry>
<index>6</index>
<type>static</type>
<internal-dst-address>
192.0.2.224/31
</internal-dst-address>
<external-dst-address>
64:ff9b::/127
</external-dst-address>
</mapping-entry>
</mapping-table>
EAMs may be enabled jointly with statefull NAT64. This example shows a NAT64 fucntion that supports static mappings:
<nat-capabilities
<nat-flavor>
nat64
</nat44-flavor>
<static-mapping-support>
true
</static-mapping-support>
<port-randomization-support>
true
</port-randomization-support>
<port-range-allocation-support>
true
</port-range-allocation-support>
<port-preservation-suport>
true
</port-preservation-suport>
<port-parity-preservation-support>
false
</port-parity-preservation-support>
<address-roundrobin-support>
true
</address-roundrobin-support>
<paired-address-pooling-support>
true
</paired-address-pooling-support>
<endpoint-independent-mapping-support>
true
</endpoint-independent-mapping-support>
<address-dependent-mapping-support>
false
</address-dependent-mapping-support>
<address-and-port-dependent-mapping-support>
false
</address-and-port-dependent-mapping-support>
<endpoint-independent-filtering-support>
true
</endpoint-independent-filtering-support>
<address-dependent-filtering>
false
</address-dependent-filtering>
<address-and-port-dependent-filtering>
false
</address-and-port-dependent-filtering>
</nat-capabilities>
The following example shows a static mapping that instructs a NAT to translate packets issued from 192.0.2.1 and with source ports in the 100-500 range to 198.51.100.1:1100-1500.
<mapping-entry>
<index>1</index>
<type>static</type>
<transport-protocol>6</transport-protocol>
<internal-src-address>
192.0.2.1
</internal-dst-address>
<internal-dst-port>
<port-range>
<start-port-number>
100
</start-port-number>
<end-port-number>
500
</end-port-number>
</port-range>
</internal-dst-port>
<external-src-address>
198.51.100.1
</external-dst-address>
<external-src-port>
<port-range>
<start-port-number>
1100
</start-port-number>
<end-port-number>
1500
</end-port-number>
</port-range>
</external-dst-port>
...
</mapping-entry>
The following example shows a static mapping that instructs a NAT to translate packets issued from 192.0.2.1/24 to 198.51.100.1/24.
<mapping-entry>
<index>1</index>
<type>static</type>
<transport-protocol>6</transport-protocol>
<internal-src-address>
192.0.2.1/24
</internal-dst-address>
<external-src-address>
198.51.100.1/24
</external-dst-address>
...
</mapping-entry>
The following XML snippet shows an example a destination NAT that is instructed to translate packets having 192.0.2.1 as a destination IP address to 198.51.100.1.
<dst-ip-address-pool>
<pool-id>1</pool-id>
<dst-in-ip-pool>
192.0.2.1
</dst-in-ip-pool>
<dst-out-ip-pool>
198.51.100.1
</dst-out-ip-pool>
</dst-ip-address-pool>
In order to instruct a NAT to translate TCP packets destined to 192.0.2.1:80 to 198.51.100.1:8080, the following XML snippet shows the static mapping to be configured on the NAT:
<mapping-entry>
<index>1</index>
<type>static</type>
<transport-protocol>6</transport-protocol>
<internal-dst-address>
192.0.2.1
</internal-dst-address>
<internal-dst-port>
<single-port-number>80</single-port-number>
</internal-dst-port>
<external-dst-address>
198.51.100.1
</external-dst-address>
<external-dst-port>
<single-port-number>8080</single-port-number>
</external-dst-port>
</mapping-entry>
In order to instruct a NAT to translate TCP packets destined to 192.0.2.1:80 (http traffic) to 198.51.100.1 and 192.0.2.1:22 (ssh traffic) to 198.51.100.2, the following XML snippet shows the static mappings to be configured on the NAT:
<mapping-entry>
<index>1</index>
<type>static</type>
<transport-protocol>6</transport-protocol>
<internal-dst-address>
192.0.2.1
</internal-dst-address>
<internal-dst-port>
<single-port-number>
80
</single-port-number>
</internal-dst-port>
<external-dst-address>
198.51.100.1
</external-dst-address>
...
</mapping-entry>
<mapping-entry>
<index>2</index>
<type>static</type>
<transport-protocol>
6
</transport-protocol>
<internal-dst-address>
192.0.2.1
</internal-dst-address>
<internal-dst-port>
<single-port-number>
22
</single-port-number>
</internal-dst-port>
<external-dst-address>
198.51.100.2
</external-dst-address>
...
</mapping-entry>
The NAT may also be instructed to proceed with both source and destination NAT. To do so, in addition to the above sample to configure destination NAT, the NAT may be provided, for example with a pool of external IP addresses (198.51.100.0/24) to use for source address translation. An example of the corresponding XML snippet is provided hereafter:
<external-ip-address-pool>
<pool-id>1</pool-id>
<external-ip-pool>
198.51.100.0/24
</external-ip-pool>
</external-ip-address-pool>
The following XML snippet shows the example of a CLAT that is configured with 2001:db8:1234::/96 as PLAT-side IPv6 prefix and 2001:db8:aaaa::/96 as CLAT-side IPv6 prefix. The CLAT is also provided with 192.0.0.1/32 (which is selected from the IPv4 service continuity prefix defined in [RFC7335]).
<nat64-prefixes>
<nat64-prefix>
2001:db8:1234::/96
</nat64-prefix>
</nat64-prefixes>
<clat-ipv6-prefixes>
<clat-ipv6-prefix>
2001:db8:aaaa::/96
</clat-ipv6-prefix>
</clat-ipv6-prefixes>
<clat-ipv4-prefixes>
<clat-ipv4-prefix>
192.0.0.1/32
</clat-ipv4-prefix>
</clat-ipv4-prefixes>
Let's consider the example of a NPTv6 translator that should rewrite packets with the source prefix (fd01:203:405:/48) with the external prefix (2001:db8:1:/48). The internal interface is "eth0" while the external interface is "eth1".
External Network: Prefix = 2001:db8:1:/48
--------------------------------------
|
|eth1
+-------------+
eth4| NPTv6 |eth2
...-----| |------...
+-------------+
|eth0
|
--------------------------------------
Internal Network: Prefix = fd01:203:405:/48
Example of NPTv6 (RFC6296)
<internal-interfaces>
</internal-interface>
eth0
<internal-interface>
</internal-interfaces>
<external-interfaces>
<external-interface>
eth1
</external-interface>
</external-interfaces>
...
<nptv6-prefixes>
<translation-id>1</translation-id>
<internal-ipv6-prefix>
fd01:203:405:/48
</internal-ipv6-prefix>
<external-ipv6-prefix>
2001:db8:1:/48
</external-ipv6-prefix>
</nptv6-prefixes>
Figure 3 shows an example of an NPTv6 that interconnects two internal networks (fd01:203:405:/48 and fd01:4444:5555:/48); each is translated using a dedicated prefix (2001:db8:1:/48 and 2001:db8:6666:/48, respectively).
Internal Prefix = fd01:4444:5555:/48
--------------------------------------
V | External Prefix
V | 2001:db8:1:/48
V +---------+ ^
V | NPTv6 | ^
V | | ^
V +---------+ ^
External Prefix | ^
2001:db8:6666:/48 | ^
--------------------------------------
Internal Prefix = fd01:203:405:/48
Figure 3: Connecting two Peer Networks (RFC6296)
<nptv6-prefixes>
<translation-id>1</translation-id>
<internal-ipv6-prefix>
fd01:203:405:/48
</internal-ipv6-prefix>
<external-ipv6-prefix>
2001:db8:1:/48
</external-ipv6-prefix>
</nptv6-prefixes>
<nptv6-prefixes>
<translation-id>2</translation-id>
<internal-ipv6-prefix>
fd01:4444:5555:/48
</internal-ipv6-prefix>
<external-ipv6-prefix>
2001:db8:6666:/48
</external-ipv6-prefix>
</nptv6-prefixes>