ssh hangs for 5 seconds for a particular machine

[Vincent Lefevre <vincent@vinc17.net>]

When connecting by SSH to a particular machine, ssh hangs for
5 seconds. The client machine doesn't matter (except for the
machine itself). For instance:

xvii:~> ssh -vvv 2>>(ts -s "%.s") ypig
[...]
0.278462 debug2: key: /home/vinc17/.ssh/id_rsa (0x7f943e415e90), explicit
0.278513 debug2: key: rsa w/o comment (0x7f943e418a60),
0.278553 debug2: key: rsa w/o comment (0x7f943e418620),
0.278591 debug2: key: /home/vinc17/.ssh/id_rsa-internal ((nil)), explicit
5.291295 debug1: Authentications that can continue: publickey,password
[...]

This is always reproducible and this problem had never occurred
before today.

Any idea?

-- 
Vincent Lefèvre <vincent@vinc17.net> - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)