[wellylug] What can cause a slow login?

[David Antliff]

On Tue, 23 Nov 2004 michael at diaspora.gen.nz wrote:
> PAM & DNS.  I saw this sort of problem (ls also worked very quickly, but
> ls -l didn't -- LDAP was also involved, looking up usernames) on a Redhat
> box that was doing DNS lookups for ::1, the IPv6 address for localhost,
> and getting 30 second timeouts from the DNS server it was using.
>
> If you do suspect DNS, login as root, use nohup and tcpdump to capture
> all traffic on port 53; something like:
>
>    nohup tcpdump -i eth0 -s 1500 -o /tmp/logfile port 53
>
> logout, log back in again, and then use Ethereal to load up the logfile
> and see if there is anything suspicious.

That reminds me - I once had an issue on a Redhat 9 server where PAM was 
causing SSH logins to take several seconds to complete. This wasn't too 
bad for interactive shell sessions, but it completely killed CVS-over-ssh 
performance (using key-pairs).

-- 
David.