[SOLVED] DNS error caused incoming messages to bounce when relayed

[sem]

Hi.

Using zcs-7.1.1_GA_3196.UBUNTU10_64.20110527011124 as a mail filter to an exchange box, using ZimbraMailTransport. All was working fine until this morning when the zimbra box received a bad dns request from one of the windows dns servers and decided that the internal exchange MTA wasn't accessible. Since then all incoming mail was unable to relay to the exchange box and bounced. I've since changed dns on the zimbra box to have it's own local zone rather than forward internal lookups to the main windows dns - it performs it's own external lookups. So it's now self contained.

Question is, have all the messages over the 2 hour period before the issue was raised gone? I've not changed the standard postfix config so is there any chance that mail delivery will be attempted? Nothing is showing in the zimbra backend as deferred.

thanks, sem

[sem]

Quick question about this - I though the postfix default deferred queue life was 5 days. In which case, if using Zimbra as a mail gateway, and passing scanned mail through to an exchange server, in the case where the exchange server becomes unavailable for a time (like that ever happens!), why didn't the messages go into the deferred queue? If they didn't by design then am I using Zimbra outside of its intended function? thanks, sem

[sem]

Just done a test with the working config on the box that pushes all incoming mail to the exchange server:

md mydomain.co.uk zimbraMailCatchAllAddress @mydomain.co.uk zimbraMailCatchAllForwardingAddress @mydomain.co.uk zimbraMailTransport smtp:exchangeserver.local:25

Disabled the connection to the exchange server to simulate exchange falling over. The problem is, all undeliverable mail being routed through zimbra is bounced immediately. I thought that it would be queued according to the default postfix settings. Is there any way to rectify this because I can't find any reference to it on the Zimbra docs.

Updated: I've looked at postfix and would smtp_defer_if_no_mx_address_found = yes be a possibility? In which case, how can I apply it because when I try postconf at cli, I get:

/opt/zimbra/postfix/sbin/postconf: warning: yes: unknown parameter

I just want zimbra to defer mail delivery if the exchange box becomes unavailable. Can anyone help - please?

thanks, sem

[sem]

Originally Posted by sem

Just done a test with the working config on the box that pushes all incoming mail to the exchange server:

md mydomain.co.uk zimbraMailCatchAllAddress @mydomain.co.uk zimbraMailCatchAllForwardingAddress @mydomain.co.uk zimbraMailTransport smtp:exchangeserver.local:25

Disabled the connection to the exchange server to simulate exchange falling over. The problem is, all undeliverable mail being routed through zimbra is bounced immediately. I thought that it would be queued according to the default postfix settings. Is there any way to rectify this because I can't find any reference to it on the Zimbra docs.

Updated: I've looked at postfix and would smtp_defer_if_no_mx_address_found = yes be a possibility? In which case, how can I apply it because when I try postconf at cli, I get:

/opt/zimbra/postfix/sbin/postconf: warning: yes: unknown parameter

I just want zimbra to defer mail delivery if the exchange box becomes unavailable. Can anyone help - please?

thanks, sem

I'm a dunce. I had a syntax error with postconf. The following has sorted my problems if the receiving exchange box goes down.

./postconf -e soft_bounce=yes to queue all mail that would otherwise be bounced as undeliverable.

./postconf -e smtp_defer_if_no_mx_address_found=yes incase of an internal problem with the exhange box that's out of my control or an unresponsive outbound smarthost - which has happened a few times in the past.

Hope these are a help to someone else.

sem