Gentoo Archives: gentoo-user

From: Florian Philipp <lists@×××××××××××.net>
To: Gentoo User List <gentoo-user@l.g.o>
Subject: [gentoo-user] SSH UseDNS without IPv6?
Date: Sat, 09 Feb 2013 18:22:56
1 Hi list!
3 I have an issue with SSH. It's a variation of the old "Set 'UseDNS no'
4 to avoid delays with faulty DNS records" theme.
6 Following setup:
7 1. I have a server with IPv6 compiled into the SSH daemon but no actual
8 IPv6 network interface.
10 2. The SSH client has no IPv6, neither compiled nor active.
12 3. The DNS server doesn't serve or support AAAA records. Apparently it
13 drops all such requests. All other records for IP and reverse lookup are
14 correct.
16 Now I'm experiencing the classic, very long delay when connecting to the
17 server via SSH because it does DNS lookups. When I look at wireshark
18 dumps, I see correctly served A and reverse lookups but the server also
19 insists on doing AAAA requests which time out.
21 I tried limiting the sshd "AddressFamily" to inet (aka IPv4) but this
22 didn't change anything. Is there another workaround or do I really have
23 to deactivate DNS lookups?
25 Thanks in advance!
26 Florian Philipp


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Subject Author
Re: [gentoo-user] SSH UseDNS without IPv6? Alan McKinnon <alan.mckinnon@×××××.com>