[H-GEN] Strangeness with POP3

Russell Stuart russell at stuart.wattle.id.au
Tue Feb 18 02:47:23 EST 2003


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One possibility is that it is doing a ident lookup - which is failing. 
The other is reverse DNS.  An easy way to check for ident to use
"netstat -anp -A inet" during the pause and see what ports the pop3
server has open.  The only way I can think of for checking for a reverse
DNS lookup is to use tcpdump.

On Tue, 2003-02-18 at 16:16, Ewan Edwards wrote:
> I haven't been able to figure out what is (not) going on here.  
> 
> I have a RH7.3 box set up as a mail server.  The MTA is Postfix 1.1.7 and all 
> the clients are serviced by imap and ipop3 daemons from the imap-2001a 
> package.  This mail server was brought on line two days ago when the Postfix 
> and Mailman configuration was migrated from another RH7.3 box.  Also migrated 
> were local user accounts, mail spool directory, and mail lists archives.
> 
> Everything seems to be working correctly except for a delay for pop clients.  
> It appears there's a delay[1] happening between when xinetd launches a new 
> instance of ipop3d and when the pop3 daemon exits.  There wasn't any delay 
> noticed on the previous box.
> 
> When I started looking in the logs (in particular /var/log/maillog), I didn't 
> see anything unusual until I noticed that the time on both /var/log/maillog 
> and /var/log/secure was always the current time[2].  At that point I decided 
> to tail -f both of them side by side and watch what happened when pop clients 
> connected.  That's how I found the where the delay is happening.
> 
> Unfortunately, I don't know enough about what is supposed to be happening to 
> know where to go from here.  After doing a bit of googling, my best guess is 
> that its something to do with pam and authenticating each pop client 
> connection.  Can anyone give me some clues or hints about where to look from 
> here - please.
> 
> 
> [1] The delay is between 16s and 21s.  See extract from /var/log/secure 
> attached.
> [2] Now that I think about it, this is probably to be expected with any 
> reasonable number of mail users.
> 

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