| Domain Name System Operations | J. Livingood |
| Internet-Draft | Comcast |
| Intended status: Best Current Practice | September 24, 2014 |
| Expires: March 28, 2015 |
In Case of DNSSEC Validation Failures, Do Not Change Resolvers
draft-livingood-dont-switch-resolvers-02
DNS Security Extensions (DNSSEC) is beginning widespread deployment. However, domain signing tools and processes are not yet as mature and reliable as is the case for non-DNSSEC-related domain administration tools and processes. As a result, some DNSSEC validation failures may occur. When these failures do occur, end users SHOULD NOT change to a non-validating DNS resolver.
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This Internet-Draft will expire on March 28, 2015.
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The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].
The Domain Name System (DNS), DNS Security Extensions (DNSSEC), and related operational practices are defined extensively [RFC1034] [RFC1035] [RFC4033] [RFC4034] [RFC4035] [RFC4398] [RFC4509] [RFC6781] [RFC5155].
DNSSEC has now entered widespread deployment. However, domain signing tools and processes are not yet as mature and reliable as is the case for non-DNSSEC-related domain administration tools and processes. As a result, some DNSSEC validation failures may occur. When these failures do occur, end users SHOULD NOT change to a non-validating DNS resolver.
A domain name can fail validation for two general reasons, a legitimate security failure such as due to an attack or compromise of some sort, or as a result of misconfiguration (mistake) on the part of an domain administrator. There is no way for end users to discern which of these issues has caused a DNSSEC-signed domain to fail validation, and end users should therefore assume that it may be due to a legitimate security problem.
End users may incorrectly interpret the failure to reach a domain due to DNSSEC-related misconfiguration as their ISP or DNS resolver operator purposely blocking access to the domain, or as a performance-related failure on the part of their ISP. In reality, these failures may be due to a security issue of which the end user is not aware.
Authoritative DNS-related mistakes and errors typically affect the entire Internet, and all DNS recursive resolver operators equally. So for example, in an A record is incorrect, an end user would get the incorrect record in a DNS response no matter what resolver they used.
In contrast to this, DNSSEC-related mistakes, errors, or validation security failures would only affect end users of validating resolvers.
As noted in Section 4 some end users may not understand why a domain fails to validate on one network but not another (or with one DNS resolver but not another) Section 5. As a result, they may consider switching to an alternative, non-validating resolver themselves. But if a domain fails DNSSEC validation and is inaccessible, this could very well be due to a security-related issue.
As a best practice: In order to be as safe and secure as possible, end users SHOULD NOT change to DNS servers that do not perform DNSSEC validation as a workaround.
Even if a website in a domain seems to look "normal" and valid, according to the DNSSEC protocol, that domain is not secure. Domains that fail DNSSEC for legitimate reasons may be in control of hackers or there could be other significant security issues with the domain. Thus, switching to a non-validating resolver to restore access to a domain that fails DNSSEC validation is NOT recommended and is potentially harmful to end user security.
The use of a non-validating DNS recursive resolver has comparatively less security capabilities than a validating resolver, since one implements DNS Security Extensions and one does not.
In the case of a DNSSEC validation failure, if an end user changes to a non-validating resolver they may subject themselves to increased security risks and threats against which DNS Security Extensions may have provided protection.
There are no privacy considerations in this document.
There are no IANA considerations in this document.
- William Brown
[RFC Editor: This section is to be removed before publication]
-00: First version published as an individual draft.
-01: Fixed nits identified by William Brown
-02: Updated prior to IETF-91
[RFC Editor: This section is to be removed before publication]