Postfix fallback_relay in Zimbra?

[adx442]

Hi there,

We're having a great experience with our Zimbra server overall, but we have a strange situation that I'm hoping to resolve.

I've configured our system to "smarthost" mode using our ISP's mail server to send, after we had a few systems refuse to talk to us based on our PTR records. It works fine, but unfortunately, our ISP's mail server is quite slow and unreliable. When we directly delivered mail, it would arrive instantly to the rest of the world. Sometimes with the ISP as a relay, it takes hours to arrive after we send. At other times, it's very fast. It's one of the reasons why we moved away from ISP e-mail in the first place ... no consistent speed of their service. Same symptoms I'm seeing now with sent mail, only.

Is it possible to use the Postfix fallback_relay option with Zimbra, so the system will attempt direct delivery, and use the smarthost relay if it gets an MX error or bounce?

Any pointers would be appreciated ... I'm new to the e-mail admin role. Thanks!

[uxbod]

Welcome to the forums

You could do though if your ISP MTA does fail to respond and you send out direct then you could hit the same problem of your email not being delivered due to bad rDNS. IMHO I would look at a third party relay server eg. DynDNS.com - Services -- MailHop Outbound who will be able to handle the outgoing email more efficiently. Other services are available I just happen to use this company myself

[cpm]

What's wrong with your PTR records?

fix that first.

[adx442]

uxbod: Thank you, I'll look into that.

cpm: Though they're set correctly on our host, we still resolve to our ISP's netblock and a few companies are blocking us based on that. My ISP wasn't willing to add a new record for us, though they don't mind us running a mail server on our business account.

We can get through to places like Yahoo and other somewhat difficult mail services, so this is a small problem overall.

I think I may have this working with what I did with this command:

postconf -e fallback_relay=ourisp.mailserver.com:25

It seems like it's trying a direct route first and then using the ISP's mail server if it fails, but I'm not 100% sure yet.