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I wrote a question the other day regarding slow authentication. disabling GSSAPIauth did the trick. However, I am now faced with another issue. When reviewing the PuTTY event logs, i now have ~20 second delay between Sent Password and Access granted.

Log below:

2012-08-13 13:30:54 Initialised HMAC-SHA1 server->client MAC algorithm
2012-08-13 13:30:57 Sent password
2012-08-13 13:31:15 Access granted
2012-08-13 13:31:15 Opened channel for session
2012-08-13 13:31:15 Allocated pty (ospeed 38400bps, ispeed 38400bps)
2012-08-13 13:31:15 Started a shell/command

Has anyone seen this slow behavior ? Again, I am using a windows 7 box with putty to connect to a RHEL5 linux server. Basically they sit on the same network.

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up vote 5 down vote accepted

This is typically caused by slow DNS lookups. Add this to your sshd_config:

UseDNS no
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Yep, this is almost always SSH doing a reverse DNS lookup on your IP address so it can log the hostname you are coming from. You'll see this delay if the server has slow DNS servers (in which case a good solution would also be to switch them to fast ones), or if the network you are connecting from doesn't have reverse DNS setup. – Grant Aug 14 '12 at 13:55
damn. noob moment for me. UseDNS no was set in the config file however it was commented out. Uncommentting the setting and we are in business. thanks. – au_stan Aug 14 '12 at 13:56
@austin - no problem. Don't kick yourself too hard. :) Also, this is the point where you ought to "accept" an answer, both in this question and the other question you posted. – EEAA Aug 14 '12 at 14:07
@erika - hahaah yes i know. couldn't do it for 8 minutes but then got pulled into a meeting :) – au_stan Aug 14 '12 at 14:53

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