Best I can tell the firewall, using a proxy, was what was slowing things down. I am confused that Jim got an immediate return of the 220 Start Banner while Jeremy got a 30 second delay. The firewall with a straight through NAT appears to be like greased lighting. It works now.

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From: plug-discuss-admin@lists.plug.phoenix.az.us [mailto:plug-discuss-admin@lists.plug.phoenix.az.us] On Behalf Of Bill Wesson
Sent: Wednesday, July 28, 2004 9:54 AM
To: plug-discuss@lists.plug.phoenix.az.us
Subject: Slow connect to SMTP

I’m getting some latency with the connect to our SMTP SENDMAIL server on Fedora Core 1 that I can’t figure out.

User’s email hangs in the outbox for 5-10 seconds before sending starts.

So I started telnet-ing (on port 25) to our Sendmail-8.12.11-1 server. (Upgrading to Sendmail 8.13 is not possible presently, nor is another SMTP handler.) Sure enough, it took a good a good 5 seconds to send back the SMTP connect banner.

I got an instant banner telnet-ing to pop3 on the same server.

The SMTP/POP3 server is in the DMZ and I’m testing from our LAN. If the travel through the firewall is the issue, then why would pop3 banner up instantly?

Our server is at mail.imarcengraver.com. Try it. Let me know è telnet mail.imarcengraver.com 25 – do you get latency?

From our LAN and through the same firewall, I can telnet port 25 to an external host ‘mail1.thenoc.com’ and get an instant banner.

Turning on AUTH (port 113) between DMZ and LAN made no difference.

At the server console a telnet to 127.0.0.1 25 yields an instant banner.

Later today, I’m going to start sniffing packets at the mail server. Anybody have any ideas before I start down this road?

Thanks,

--Bill