draft-ietf-ipsecme-split-dns-00.txt   draft-ietf-ipsecme-split-dns-01.txt 
Network T. Pauly Network T. Pauly
Internet-Draft Apple Inc. Internet-Draft Apple Inc.
Intended status: Standards Track P. Wouters Intended status: Standards Track P. Wouters
Expires: September 14, 2017 Red Hat Expires: January 20, 2018 Red Hat
March 13, 2017 July 19, 2017
Split DNS Configuration for IKEv2 Split DNS Configuration for IKEv2
draft-ietf-ipsecme-split-dns-00 draft-ietf-ipsecme-split-dns-01
Abstract Abstract
This document defines two Configuration Payload Attribute Types for This document defines two Configuration Payload Attribute Types for
the IKEv2 protocol that add support for private DNS domains. These the IKEv2 protocol that add support for private DNS domains. These
domains should be resolved using DNS servers reachable through an domains should be resolved using DNS servers reachable through an
IPsec connection, while leaving all other DNS resolution unchanged. IPsec connection, while leaving all other DNS resolution unchanged.
This approach of resolving a subset of domains using non-public DNS This approach of resolving a subset of domains using non-public DNS
servers is referred to as "Split DNS". servers is referred to as "Split DNS".
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 14, 2017. This Internet-Draft will expire on January 20, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Background . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Background . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Protocol Exchange . . . . . . . . . . . . . . . . . . . . . . 3 3. Protocol Exchange . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Configuration Request . . . . . . . . . . . . . . . . . . 4 3.1. Configuration Request . . . . . . . . . . . . . . . . . . 4
3.2. Configuration Reply . . . . . . . . . . . . . . . . . . . 4 3.2. Configuration Reply . . . . . . . . . . . . . . . . . . . 4
3.3. Mapping DNS Servers to Domains . . . . . . . . . . . . . 5 3.3. Mapping DNS Servers to Domains . . . . . . . . . . . . . 5
3.4. Example Exchanges . . . . . . . . . . . . . . . . . . . . 5 3.4. Example Exchanges . . . . . . . . . . . . . . . . . . . . 5
3.4.1. Simple Case . . . . . . . . . . . . . . . . . . . . . 5 3.4.1. Simple Case . . . . . . . . . . . . . . . . . . . . . 5
3.4.2. Requesting Domains and DNSSEC trust anchors . . . . . 5 3.4.2. Requesting Domains and DNSSEC trust anchors . . . . . 6
4. Payload Formats . . . . . . . . . . . . . . . . . . . . . . . 6 4. Payload Formats . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. INTERNAL_DNS_DOMAIN Configuration Attribute Type . . . . 6 4.1. INTERNAL_DNS_DOMAIN Configuration Attribute Type . . . . 6
4.2. INTERNAL_DNSSEC_TA Configuration Attribute . . . . . . . 7 4.2. INTERNAL_DNSSEC_TA Configuration Attribute . . . . . . . 7
5. Split DNS Usage Guidelines . . . . . . . . . . . . . . . . . 7 5. Split DNS Usage Guidelines . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9 6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.1. Normative References . . . . . . . . . . . . . . . . . . 10 8.1. Normative References . . . . . . . . . . . . . . . . . . 10
8.2. Informative References . . . . . . . . . . . . . . . . . 10 8.2. Informative References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
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For the purposes of this document, DNS resolution servers accessible For the purposes of this document, DNS resolution servers accessible
through an IPsec connection will be referred to as "internal DNS through an IPsec connection will be referred to as "internal DNS
servers", and other DNS servers will be referred to as "external DNS servers", and other DNS servers will be referred to as "external DNS
servers". servers".
A client using these configuration payloads will be able to request A client using these configuration payloads will be able to request
and receive Split DNS configurations using the INTERNAL_DNS_DOMAIN and receive Split DNS configurations using the INTERNAL_DNS_DOMAIN
and INTERNAL_DNSSEC_TA configuration attributes. The client device and INTERNAL_DNSSEC_TA configuration attributes. The client device
can use the internal DNS server(s) for any DNS queries within the can use the internal DNS server(s) for any DNS queries within the
assigned domains. DNS queries for other domains should be send to assigned domains. DNS queries for other domains should be send to
its regular external DNS server. regular external DNS server.
1.1. Requirements Language 1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
2. Background 2. Background
Split DNS is a common configuration for enterprise VPN deployments, Split DNS is a common configuration for enterprise VPN deployments,
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In order to negotiate which domains are considered internal to an In order to negotiate which domains are considered internal to an
IKEv2 tunnel, initiators indicate support for Split DNS in their IKEv2 tunnel, initiators indicate support for Split DNS in their
CFG_REQUEST payloads, and responders assign internal domains (and CFG_REQUEST payloads, and responders assign internal domains (and
DNSSEC trust anchors) in their CFG_REPLY payloads. When Split DNS DNSSEC trust anchors) in their CFG_REPLY payloads. When Split DNS
has been negotiated, the existing DNS server configuration attributes has been negotiated, the existing DNS server configuration attributes
will be interpreted as internal DNS servers that can resolve will be interpreted as internal DNS servers that can resolve
hostnames within the internal domains. hostnames within the internal domains.
3.1. Configuration Request 3.1. Configuration Request
To indicate support for Split DNS, an initiator sends a CFG_REQUEST To indicate support for Split DNS, an initiator includes one more
payload MAY with one INTERNAL_DNS_DOMAIN attributes as defined in more INTERNAL_DNS_DOMAIN attributes as defined in Section 4 as part
Section 4. If an INTERNAL_DNS_DOMAIN attribute is included in the of the CFG_REQUEST payload. If an INTERNAL_DNS_DOMAIN attribute is
CFG_REQUEST, the initiator SHOULD also include one or more included in the CFG_REQUEST, the initiator SHOULD also include one or
INTERNAL_IP4_DNS and INTERNAL_IP6_DNS attributes in its CFG_REQUEST. more INTERNAL_IP4_DNS and INTERNAL_IP6_DNS attributes in the
CFG_REQUEST.
The length of the INTERNAL_DNS_DOMAIN attribute sent by the initiator The INTERNAL_DNS_DOMAIN attribute sent by the initiator is usually
is zero. empty but MAY contain a suggested domain name.
The absence of INTERNAL_DNS_DOMAIN attributes in the CFG_REQUEST The absence of INTERNAL_DNS_DOMAIN attributes in the CFG_REQUEST
payload indicates that the initiator does not support or is unwilling payload indicates that the initiator does not support or is unwilling
to accept Split DNS configuration. to accept Split DNS configuration.
To indicate support for DNSSEC, an initiator sending a CFG_REQUEST To indicate support for DNSSEC, an initiator includes one or more
payload MAY include one INTERNAL_DNS_TA attributes as defined in INTERNAL_DNS_TA attributes as defined in Section 4 as part of the
Section 4. CFG_REQUEST payload. If an INTERNAL_DNS_TA attriute is included in
the CFG_REQUEST, the initiator SHOULD also include one or more
INTERNAL_DNS_DOMAIN attributes in the CFG_REQUEST.
An initiator MAY convey its current DNSSEC trust anchors for the An initiator MAY convey its current DNSSEC trust anchors for the
domain specified in the INTERNAL_DNS_DOMAIN attribute. If it does domain specified in the INTERNAL_DNS_DOMAIN attribute. If it does
not wish to convey this information, it MUST use a length of 0. not wish to convey this information, it MUST use a length of 0.
The absence of INTERNAL_DNS_TA attributes in the CFG_REQUEST payload The absence of INTERNAL_DNS_TA attributes in the CFG_REQUEST payload
indicates that the initiator does not support or is unwilling to indicates that the initiator does not support or is unwilling to
accept DNSSEC trust anchor configuration. accept DNSSEC trust anchor configuration.
3.2. Configuration Reply 3.2. Configuration Reply
Responders MAY send one or more INTERNAL_DNS_DOMAIN attributes in Responders MAY send one or more INTERNAL_DNS_DOMAIN attributes in
their CFG_REPLY payload if the CFG_REQUEST contained at least one their CFG_REPLY payload. If an INTERNAL_DNS_DOMAIN attribute is
INTERNAL_DNS_DOMAIN attribute. If the CFG_REQUEST did not contain an included in the CFG_REPLY, the responder MUST also include one or
INTERNAL_DNS_DOMAIN attribute, the responder MUST NOT include an both of the INTERNAL_IP4_DNS and INTERNAL_IP6_DNS attributes in the
INTERNAL_DNS_DOMAIN attribute in the CFG_REPLY. If an CFG_REPLY. These DNS server configurations are necessary to define
INTERNAL_DNS_DOMAIN attribute is included in the CFG_REPLY, the which servers should receive queries for hostnames in internal
responder SHOULD also include one or both of the INTERNAL_IP4_DNS and domains. If the CFG_REQUEST included an INTERNAL_DNS_DOMAIN
INTERNAL_IP6_DNS attributes in its CFG_REPLY. These DNS server attribute, but the CFG_REPLY does not include an INTERNAL_DNS_DOMAIN
configurations are necessary to define which servers should receive attribute, the initiator should behave as if Split DNS configurations
queries for hostnames in internal domains. If the CFG_REQUEST are not supported by the server.
included an INTERNAL_DNS_DOMAIN attribute, but the CFG_REPLY does not
include an INTERNAL_DNS_DOMAIN attribute, the initiator should behave
as if Split DNS configurations are not supported by the server.
Each INTERNAL_DNS_DOMAIN represents a domain that the DNS servers Each INTERNAL_DNS_DOMAIN represents a domain that the DNS servers
address listed in INTERNAL_IP4_DNS and INTERNAL_IP6_DNS can resolve. address listed in INTERNAL_IP4_DNS and INTERNAL_IP6_DNS can resolve.
If the CFG_REQUEST included INTERNAL_DNS_DOMAIN attributes with non- If the CFG_REQUEST included INTERNAL_DNS_DOMAIN attributes with non-
zero lengths, the content MUST be ignored. zero lengths, the content MAY be ignored or be interpreted as a
suggestion by the responder.
For each DNS domain specified in an INTERNAL_DNS_DOMAIN attribute, For each DNS domain specified in an INTERNAL_DNS_DOMAIN attribute,
one or more INTERNAL_DNSSEC_TA attributes MAY be included by the one or more INTERNAL_DNSSEC_TA attributes MAY be included by the
responder. This attribute lists the corresponding DSSNEC trust responder. This attribute lists the corresponding internal DNSSEC
anchor in the DNS wire format of a DS record as specified in trust anchor in the DNS wire format of a DS record as specified in
[RFC4034]. The INTERNAL_DNSSEC_TA attribute MUST immediately follow [RFC4034]. The INTERNAL_DNSSEC_TA attribute MUST immediately follow
the INTERNAL_DNS_DOMAIN attribute that it applies to. the INTERNAL_DNS_DOMAIN attribute that it applies to.
3.3. Mapping DNS Servers to Domains 3.3. Mapping DNS Servers to Domains
All DNS servers provided in the CFG_REPLY MUST support resolving All DNS servers provided in the CFG_REPLY MUST support resolving
hostnames within all INTERNAL_DNS_DOMAIN domains. In other words, hostnames within all INTERNAL_DNS_DOMAIN domains. In other words,
the INTERNAL_DNS_DOMAIN attributes in a CFG_REPLY payload form a the INTERNAL_DNS_DOMAIN attributes in a CFG_REPLY payload form a
single list of Split DNS domains that applies to the entire list of single list of Split DNS domains that applies to the entire list of
INTERNAL_IP4_DNS and INTERNAL_IP6_DNS attributes. INTERNAL_IP4_DNS and INTERNAL_IP6_DNS attributes.
3.4. Example Exchanges 3.4. Example Exchanges
3.4.1. Simple Case 3.4.1. Simple Case
In this example exchange, the initiator requests INTERNAL_IP4_DNS and In this example exchange, the initiator requests INTERNAL_IP4_DNS and
INTERNAL_DNS_DOMAIN attributes in its CFG_REQUEST, but does not INTERNAL_DNS_DOMAIN attributes in the CFG_REQUEST, but does not
specify any value for either. This indicates that it supports Split specify any value for either. This indicates that it supports Split
DNS, but has no preference for which DNS requests should be routed DNS, but has no preference for which DNS requests should be routed
through the tunnel. through the tunnel.
The responder replies with two DNS server addresses, and two internal The responder replies with two DNS server addresses, and two internal
domains, "example.com" and "city.other.com". domains, "example.com" and "city.other.com".
Any subsequent DNS queries from the initiator for domains such as Any subsequent DNS queries from the initiator for domains such as
"www.example.com" should use 198.51.100.2 or 198.51.100.4 to resolve. "www.example.com" should use 198.51.100.2 or 198.51.100.4 to resolve.
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CP(CFG_REPLY) = CP(CFG_REPLY) =
INTERNAL_IP4_ADDRESS(198.51.100.234) INTERNAL_IP4_ADDRESS(198.51.100.234)
INTERNAL_IP4_DNS(198.51.100.2) INTERNAL_IP4_DNS(198.51.100.2)
INTERNAL_IP4_DNS(198.51.100.4) INTERNAL_IP4_DNS(198.51.100.4)
INTERNAL_DNS_DOMAIN(example.com) INTERNAL_DNS_DOMAIN(example.com)
INTERNAL_DNS_DOMAIN(city.other.com) INTERNAL_DNS_DOMAIN(city.other.com)
3.4.2. Requesting Domains and DNSSEC trust anchors 3.4.2. Requesting Domains and DNSSEC trust anchors
In this example exchange, the initiator requests INTERNAL_IP4_DNS, In this example exchange, the initiator requests INTERNAL_IP4_DNS,
INTERNAL_DNS_DOMAIN and INTERNAL_DNS_TA attributess in its INTERNAL_DNS_DOMAIN and INTERNAL_DNS_TA attributess in the
CFG_REQUEST CFG_REQUEST
Any subsequent DNS queries from the initiator for domains such as Any subsequent DNS queries from the initiator for domains such as
"www.example.com" or "city.other.com" would be DNSSEC validated using "www.example.com" or "city.other.com" would be DNSSEC validated using
the DNSSEC trust anchor received in the CFG_REPLY the DNSSEC trust anchor received in the CFG_REPLY
In this example, the initiator has no existing DNSSEC trust anchors In this example, the initiator has no existing DNSSEC trust anchors
would the requested domain. the "example.com" dommain has DNSSEC would the requested domain. the "example.com" dommain has DNSSEC
trust anchors that are returned, while the "other.com" domain has no trust anchors that are returned, while the "other.com" domain has no
DNSSEC trust anchors DNSSEC trust anchors
CP(CFG_REQUEST) = CP(CFG_REQUEST) =
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| | | |
+---------------------------------------------------------------+ +---------------------------------------------------------------+
o Reserved (1 bit) - Defined in IKEv2 RFC [RFC7296]. o Reserved (1 bit) - Defined in IKEv2 RFC [RFC7296].
o Attribute Type (15 bits) 25 - INTERNAL_DNS_DOMAIN. o Attribute Type (15 bits) 25 - INTERNAL_DNS_DOMAIN.
o Length (2 octets, unsigned integer) - Length of domain name. o Length (2 octets, unsigned integer) - Length of domain name.
o Domain Name (0 or more octets) - A domain or subdomain used for o Domain Name (0 or more octets) - A domain or subdomain used for
Split DNS rules, such as example.com. This is a string of ASCII Split DNS rules, such as example.com in DNS wire format.
characters with labels separated by dots, with no trailing dot,
using IDNA [RFC5890] for non-ASCII DNS domains. The value is NOT
null-terminated.
4.2. INTERNAL_DNSSEC_TA Configuration Attribute 4.2. INTERNAL_DNSSEC_TA Configuration Attribute
1 2 3 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-----------------------------+-------------------------------+ +-+-----------------------------+-------------------------------+
|R| Attribute Type | Length | |R| Attribute Type | Length |
+-+-----------------------------+---------------+---------------+ +-+-----------------------------+---------------+---------------+
| Key Tag | Algorithm | Digest Type | | Key Tag | Algorithm | Digest Type |
+-------------------------------+---------------+---------------+ +-------------------------------+---------------+---------------+
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o Key Tag value (0 or 2 octets, unsigned integer) - Key Tag as o Key Tag value (0 or 2 octets, unsigned integer) - Key Tag as
specified in [RFC4034] Section 5.1 specified in [RFC4034] Section 5.1
o DNSKEY algorithm (0 or 1 octet) - Value from the IANA DNS Security o DNSKEY algorithm (0 or 1 octet) - Value from the IANA DNS Security
Algorithm Numbers Registry Algorithm Numbers Registry
o DS algorithm (0 or 1 octet) - Value from the IANA Delegation o DS algorithm (0 or 1 octet) - Value from the IANA Delegation
Signer (DS) Resource Record (RR) Type Digest Algorithms Registry Signer (DS) Resource Record (RR) Type Digest Algorithms Registry
o Digest (0 or more octets) - The raw digest as specified in o Digest (0 or more octets) - The digest as specified in [RFC4034]
[RFC4034] Section 5.1 Section 5.1 in wire format.
5. Split DNS Usage Guidelines 5. Split DNS Usage Guidelines
If a CFG_REPLY payload contains no INTERNAL_DNS_DOMAIN attributes, If a CFG_REPLY payload contains no INTERNAL_DNS_DOMAIN attributes,
the client MAY use the provided INTERNAL_IP4_DNS or INTERNAL_IP6_DNS the client MAY use the provided INTERNAL_IP4_DNS or INTERNAL_IP6_DNS
servers as the default DNS server(s) for all queries. servers as the default DNS server(s) for all queries.
If a client is configured by local policy to only accept a limited If a client is configured by local policy to only accept a limited
number of INTERNAL_DNS_DOMAIN values, the client MUST ignore any number of INTERNAL_DNS_DOMAIN values, the client MUST ignore any
other INTERNAL_DNS_DOMAIN values. other INTERNAL_DNS_DOMAIN values.
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For each INTERNAL_DNS_DOMAIN entry in a CFG_REPLY payload that is not For each INTERNAL_DNS_DOMAIN entry in a CFG_REPLY payload that is not
prohibited by local policy, the client MUST use the provided prohibited by local policy, the client MUST use the provided
INTERNAL_IP4_DNS or INTERNAL_IP6_DNS DNS servers as the only INTERNAL_IP4_DNS or INTERNAL_IP6_DNS DNS servers as the only
resolvers for the listed domains and its sub-domains and it MUST NOT resolvers for the listed domains and its sub-domains and it MUST NOT
attempt to resolve the provided DNS domains using its external DNS attempt to resolve the provided DNS domains using its external DNS
servers. servers.
If the initiator host is configured to block DNS answers containing If the initiator host is configured to block DNS answers containing
IP addresses from special IP address ranges such as those of IP addresses from special IP address ranges such as those of
[RFC1918], the initiator SHOULD allow the DNS domains listed in the [RFC1918], the initiator SHOULD allow the DNS domains listed in the
INTERNAL_DNS_DOMAIN attributes to contain those Special IP addresses INTERNAL_DNS_DOMAIN attributes to contain those Special IP addresses.
that are covered by the Child SA's.
If a CFG_REPLY contains one or more INTERNAL_DNS_DOMAIN attributes If a CFG_REPLY contains one or more INTERNAL_DNS_DOMAIN attributes
and its local policy does not forbid these values, the client MUST and its local policy does not forbid these values, the client MUST
configure its DNS resolver to resolve those domains and all their configure its DNS resolver to resolve those domains and all their
subdomains using only the DNS resolver(s) listed in that CFG_REPLY subdomains using only the DNS resolver(s) listed in that CFG_REPLY
message. If those resolvers fail, those names MUST NOT be resolved message. If those resolvers fail, those names MUST NOT be resolved
using any other DNS resolvers. Other domain names SHOULD be resolved using any other DNS resolvers. Other domain names SHOULD be resolved
using some other external DNS resolver(s), configured independently using some other external DNS resolver(s), configured independently
from IKE. Queries for these other domains MAY be sent to the from IKE. Queries for these other domains MAY be sent to the
internal DNS resolver(s) listed in that CFG_REPLY message, but have internal DNS resolver(s) listed in that CFG_REPLY message, but have
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"example.com", "www.example.com" and "mail.eng.example.com" MUST be "example.com", "www.example.com" and "mail.eng.example.com" MUST be
resolved using the internal DNS resolver(s), but "anotherexample.com" resolved using the internal DNS resolver(s), but "anotherexample.com"
and "ample.com" SHOULD NOT be resolved using the internal resolver and "ample.com" SHOULD NOT be resolved using the internal resolver
and SHOULD use the system's external DNS resolver(s). and SHOULD use the system's external DNS resolver(s).
An initiator SHOULD ignore INTERNAL_DNS_DOMAIN attributes containing An initiator SHOULD ignore INTERNAL_DNS_DOMAIN attributes containing
domains that are designated Special Use Domain Names in [RFC6761], domains that are designated Special Use Domain Names in [RFC6761],
such as "local", "localhost", "invalid", etc. Although it may such as "local", "localhost", "invalid", etc. Although it may
explicitly wish to support some Special Use Domain Names. explicitly wish to support some Special Use Domain Names.
When an IPsec connection is terminated, the DNS forwarding must be When an IKE SA is terminated, the DNS forwarding must be
unconfigured. The DNS forwarding itself MUST be be deleted. All unconfigured. The DNS forwarding itself MUST be be deleted. All
cached data of the INTERNAL_DNS_DOMAIN provided DNS domainis MUST be cached data of the INTERNAL_DNS_DOMAIN provided DNS domainis MUST be
flushed. This includes negative cache entries. Obtained DNSSEC flushed. This includes negative cache entries. Obtained DNSSEC
trust anchors MUST be removed from the list of trust anchors. The trust anchors MUST be removed from the list of trust anchors. The
outstanding DNS request queue MUST be cleared. outstanding DNS request queue MUST be cleared.
INTERNAL_DNS_DOMAIN and INTERNAL_DNSSEC_TA attributes SHOULD only be INTERNAL_DNS_DOMAIN and INTERNAL_DNSSEC_TA attributes SHOULD only be
used on split tunnel configurations where only a subset of traffic is used on split tunnel configurations where only a subset of traffic is
routed into a private remote network using the IPsec connection. If routed into a private remote network using the IPsec connection. If
all traffic is routed over the IPsec connection, the existing global all traffic is routed over the IPsec connection, the existing global
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