Loosing SMTP Messages behind pix affter mail is turn off.

[fisko]

I have SMTP server behind pix with NAT and SMTP permit inside. While mail server working it is ok. When I turn off mail server, i loose mail that i try to send from outside and also i dont get message dilivery failure as reply. where is the ,message and how to fix this.

REGARDS and THANKS!!!!

fisko

[ehirsel]

How are you sending the messages from the outside?

How many mail servers do you have behind the pix, just the one you mentioned?

Also as a test, with the mail server off, try to telnet to the mail-server's ip address on port 25 and see if you get a banner screen.

One thing to check for is what address do outside users see your mail server as? I.E., what do you nat the mail server to? If it is the pix's outside interface and you are doing pat/nat redirection that may help explain why you are losing mail.

[fisko]

Thanks for assistance!

I have one mail server. When I turn off mail server I can not telnet to mail from outside.

I am natting Inside IP to outside Ip which is different from pixs outside interface.

How mail servers sending mail to me when the server is turned off and inside IP is down.

They see outside IP and send smtp to outside ip.

Where are these messages and how pix handle them?

THANKS FOR ANY HELP!!!!

REGARDS

fisko

[mostiguy]

when your mail server is down, people cannot send mail to it. that mail will sit on their smtp servers for probably up to 48 hours before it is discarded.

install a second mail server, or contract an isp or someone to act as the secondary mx record for your domain (you would create another mx record in dns for that mail server, and they would configure that server to accept email for your domain. once your mail server comes back on line, mail should flow from that server to yours)

[fisko]

OK If it is that way, why users that try to send messages from outside never get the message that message is discarded or not delivered?

Regards

fisko

[ehirsel]

I depends upon the user's mail exchanger configuration - some may wait longer than others, and some may configured not to send undeliverable messages to the user and silently drop them. With the recent spate of spam and false/spoofed messaging, I could see the latter being used.

What is important is this: How long is your mail server down before it comes back up. If it is within 48 hours, I would reasonably expect that within 12 hours, any delayed message should get thru? Can you tell if this is the case?