From: shyouhei@...
Date: 2018-07-25T07:44:45+00:00
Subject: [ruby-core:88100] [Ruby trunk Bug#14922][Assigned] Resolv getaddresses ignores AAAA records for IPv6

Issue #14922 has been updated by shyouhei (Shyouhei Urabe).

Status changed from Open to Assigned
Assignee set to akr (Akira Tanaka)

Mmm, I think this is a real bug.

RUBYOPT does not work well in this case because resolve.rb is a library while RUBYOPT is for the process.  Adding parameter to the constructor is an option though.

----------------------------------------
Bug #14922: Resolv getaddresses ignores AAAA records for IPv6
https://bugs.ruby-lang.org/issues/14922#change-73122

* Author: dlampa (Donovan Lampa)
* Status: Assigned
* Priority: Normal
* Assignee: akr (Akira Tanaka)
* Target version: 
* ruby -v: 2.5.1
* Backport: 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN
----------------------------------------
I'd like some feedback here as I'm not totally convinced this is a bug quite yet. I may have done something silly with my DNS configuration.

I have a local DNS server set up with the following /etc/resolv.conf
~~~
[root@ip-10-20-0-181 ~]# cat /etc/resolv.conf
# Generated by NetworkManager
search us-east-2.compute.internal
nameserver ::1
~~~

And the following zone configured in bind
~~~
[root@ip-10-20-0-181 ~]# cat /var/named/test.net.zone
$TTL    86400

@       IN      SOA     test.net root.test.net (
        2016050204
        3600
        900
        604800
        86400
)

@               IN      NS         testbox
testbox         IN      AAAA       2600:1f16:a82:9b01:5a89:f06f:dde4:7b5e
malware         IN      AAAA       2600:1f16:a82:9b01:cab2:a7c0:e2cb:1162
goodware        IN      A          10.20.0.181
~~~

It appears that Resolv needs me to explicitly request the AAAA resource for malware.test.net in order to get the IPv6 address in this situation. It doesn't seem to need that for IPv4.

~~~
irb(main):001:0> require 'resolv'
=> true
irb(main):002:0> resolver = Resolv.new
=> #<Resolv:0x0000000001db3c78 @resolvers=[#<Resolv::Hosts:0x0000000001db3c28 @filename="/etc/hosts", @mutex=#<Thread::Mutex:0x0000000001db3bd8>, @initialized=nil>, #<Resolv::DNS:0x0000000001db3b88 @mutex=#<Thread::Mutex:0x0000000001db3b38>, @config=#<Resolv::DNS::Config:0x0000000001db3ae8 @mutex=#<Thread::Mutex:0x0000000001db3a48>, @config_info=nil, @initialized=nil, @timeouts=nil>, @initialized=nil>]>
irb(main):003:0> resolver.getaddresses("malware.test.net")
=> []
irb(main):004:0> resolver.getaddresses("goodware.test.net")
=> ["10.20.0.181"]
irb(main):005:0> dns_resolver = Resolv::DNS.new
=> #<Resolv::DNS:0x0000000001d2a040 @mutex=#<Thread::Mutex:0x0000000001d29fa0>, @config=#<Resolv::DNS::Config:0x0000000001d29f78 @mutex=#<Thread::Mutex:0x0000000001d29e60>, @config_info=nil, @initialized=nil, @timeouts=nil>, @initialized=nil>
irb(main):006:0> dns_resolver.getresource("malware.test.net", Resolv::DNS::Resource::IN::AAAA)
=> #<Resolv::DNS::Resource::IN::AAAA:0x0000000001cbaf38 @address=#<Resolv::IPv6 2600:1F16:A82:9B01:CAB2:A7C0:E2CB:1162>, @ttl=86400>
~~~

Based on Resolv's documentation I would expect to get back the IPv6 address for malware.test.net



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