EXIM has incredible high timeout before accepting connection.

[ispro]

Recently we started having strange timeout problem.

While trying to connect to smtp we see welcome (Exim 4.43 #1 ....) message after FULL THREE MINUTES or so!

At the same time /var/log/exim_mainlog shows that Exim accepting connections:
SMTP connection from [66.66.2.158]:4468 I=[67.18.*****]:25 (TCP/IP connection count = 62)
SMTP connection from [12.227.159.214]:4468 I=[67.18.*****]:25 (TCP/IP connection count = 63)
SMTP connection from [66.176.91.125]:4468 I=[67.18.*****]:25 (TCP/IP connection count = 64)

After reaching 100 connection it fails to any new one (btw, increasing smtp_accept_max to 200, 300, even 1000 not helps).

I'm really confused.

Please, anyone, help us to locate problem's source!

[ispro]

Just in case someone come to this ticket...

The active TrinityOS rc.firewall (iptables based) caused this delay.

I not discovered how to tune it (or its settings) to allow smtp works normally, without the delay (especially because no other servers affected!) yet...

If someone know where I need to take a look (perhaps some specific ports or so on) let me know, please.

[chirpy]

If you're having problems with that firewall, have you tried a different one, e.g. APF?

[ispro]

No, I didn't.
This firewall proved that it is simple, but stable.
Wonder, it is just iptables one! No more special instructions like in APF.
Anyway, it stops something. So, APF will do the same.

Looks like Exim trying to do something with addresses that originating connections, perhaps reverse lookup or so? How to allow this?..

[chirpy]

I'm confused, two posts up you said that the firewall was the problem. IF the firewall is the problem, then the problem isn't with exim

[ispro]

OK

Which ports should be open at firewall for Exim not delayed with welcome message?