Hello,
I have 2 postfix mail relays (similar postfix configuration) which
forward my incoming emails to an Exchange Server, and I have problems
after Exchange reboots. One mail relay (Relay2) “hooks” Exchange and
starts over sending mails and one (Relay1) keeps timing out though the
Exchange server is up and the connections can be established on TCP 25
with a telnet connection.
My Postfix version : 2.3.8-2
My OS : Ubuntu Feisty
My network topology is :
- Relay1 has a public IP and forwards incoming mail to a NATed firewall
(pfsense) which forwards TCP 25 to the internal IP of my Exchange server
- Relay2 has a public IP and forwards incoming mail without NAT and only
with its routes to the internal IP of my Exchange server
During the reboot of the Exchange server, the logs on Relay are similar to :
Sep 15 12:13:33 relay postfix/qmgr[10428]: 65E2F3C03F: to=<
[EMAIL PROTECTED]>, relay=none, delay=0.28, delays=0.18/0.1/0/0, dsn=4.4.1,
status=defe
rred (delivery temporarily suspended: connect to
192.168.0.250[192.168.0.250]: Connection timed out)
When the Exchange server’s reboot is done and its services started,
Relay2 forwards new incoming emails to my Exchange server, and old ones
will be resent later; without further action.
But Relay1 keeps timing out (meanwhile I can establish a connection to
the NATed IP with telnet), even for new mails, until I restart Postfix.
Postfix is really great, but I need to have them autonomous on this
point, because I’m not in charge of the Exchange server, and the
Exchange reboots can happen outside of my working hours.
I’ve already spent a few hours googling, but for now, I don’t have any
serious clue … I’ll plan during the next week an Ethereal frame capture
to see if I can find the problem
Has someone had this kind of problem in the past ?
- Is that a network problem ? Does it come from my pfsense firewall ?
- Is there a value to set in Postfix ? I’ve seen the value
“default_destination_concurrency_failed_cohort_limit”, which I can
disable, but I don’t have Postfix 2.5 installed and this value doesn’t
explain why I do have an asymmetric behavior between my two relays
- Any other clue ?
Thanks a lot and sorry for my bad english ;-)
Milosz SZOT
ADOC System Engineer
[EMAIL PROTECTED]
