[imp] Slow logins and sends from one ISP

[Brett Charbeneau]

 	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^)


-- 
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Brett Charbeneau, GSEC Gold, GCIH Gold
Network Administrator
Williamsburg Regional Library
7770 Croaker Road
Williamsburg, VA 23188-7064
(757)259-4044          www.wrl.org
(757)259-4079 (fax)    brett at wrl.org
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