Roaming users cannot authenticate to SMTP

[ekkas]

I need to get users with roaming connections (connecting through other ISP) to be able to still use our server to send mail so they do not have to swop smtp servers as they plug into different networks.
Even with SMTP authentication enabled, it gives them a relay access denied error.

I checked MTA settings and 'Enable authentication' is ticked, but I'm obviously missing something else.

Thanks
Ekkas

[ewilen]

I don't think that Zimbra will allow relaying for mail submitted via SMTP port 25, if you have Authentication checked.

What port are your mail clients using to connect to Zimbra? They should be using 587 (submission) or 465 (SMTPS) for secure authentication. The clients should also support TLS. (You might be able to get away with just ticking SSL on the client's preferences. E.g., tell it to use SMTP to connect to port 465 with SSL enabled.)