[imp] Slow logins and sends from one ISP

[Andrew Morgan]

On Tue, 15 May 2007, Brett Charbeneau wrote:

> 	First, MANY thanks to everyone who works so hard making IMP such a
> rocking piece of software! My users are happy as pigs with the entire Horde
> suite, but IMP meets our needs in many wonderful ways.
> 	I'd be grateful for any hints or help anyone can find time to offer with
> a particularly strange (to me anyway) problem two of my users are experiencing!
> I've scoured the list archives, WiKi and FAQ and found somne hints but nothing
> I've tried makes a difference.
>
> SPECIFICS on the IMP SERVER:
>
> 	Kernel: 2.6.8-3 (Debian 3.1); Athlon 1150 w/ 1 GB of RAM
> 	Horde: 3.0.4; Imp: 4.0.2; PHP Version: 4.3.10-20
>
> SPECIFICS on the MAIL SERVER:
>
> 	Kernel: 2.6.8-3 (Debian 3.1); P4 3.20GHz w/ 4 GB of RAM
> 	uw-imapd: 7:2002edebian1-11sarge1; Sendmail: 8.13.4
>
> DESCRIPTION OF ISSUE:
>
> 	We have about 220 total users and never more than 20 or so
> simultaneously in IMP (many people use Pine or email clients). The mail server
> has SCSI drives with 160.000MB/s transfers (swap partition loaded into RAM) and
> the load average is below zero every time I check so I don't think it's an I/O
> or load problem on the mail server end. We connect to the mail server's uw-imapd
> via port 993 (SSL) and start this service on the mail server from inetd.conf
> with this line:
>
> imaps   stream  tcp     nowait.1000     root    /usr/sbin/tcpd /usr/sbin/imapd
>
> 	KEY INFO: IMP response time and overall speed within our network and
> from the Internet in general seems to be fine.
> 	However, one of my staff is a Mac OSX user and Cox at Home customer and no
> matter what browser she uses (Safari, FireFox, or Opera) it takes 19 seconds to
> complete a login and 25 seconds to send a message from her home. She has a
> static IP from Cox.
> 	Another user (Win XP) is on AOL dial-up with dynamic IP assignment and
> gets similar results although I've always written that off to the modem
> bottleneck.
> 	Neither user has a particularly large INBOX.
> 	Since things seem to work great on our internal network I'm stumped as
> to where to begin troubleshooting this, although the temptation to blame the
> ISPs is strong.
> 	It sounds like something's up with DNS and I've made sure the DNS
> servers listed in the IMP server's resolv.conf file (our primary and secondary
> DNS machines) are accessible to the server AND from the outside world.
> 	I found mention in the list of uw-imapd might be doing identd lookups to
> itself, but I'm not seeing any of this sort of traffic being blocked in my log
> output from iptables.
> 	We do use turba but since the everything works well locally I haven't
> suspected a misconfiguration in the sources.php file. I have other users
> employing imap with their (local) email clients and all seems well at the mail
> server.
> 	Anyone got any idea what's happening here - or can I blame Cox and AOL?
> =8^)

How long does it take to login with an IMAP mail client such as 
Thunderbird?  I'd suspect the problem lies with uw-imapd.

 	Andy