[SOLVED] Yet another SMTP authentication issue

[EdMartin]

This is probably not a Zimbra issue. But there are lots of bright people here, some of whom may have experienced a similar problem and can shed some light.

Living in South Florida, we are prone to momentary power outages, when the power goes off for a second and then comes right back on again. This often results in our having to reset all the clocks in the house!

The last time this happened, the wireless router (a perfectly normal Linksys WRT54GS v.7) that runs my home network became misconfigured. Instead of being assigned a public IP address by my cable modem, the WAN port had somehow acquired a private 192.168.x.x address. It took two interventions from my cable company to get it to behave itself and once again have a public WAN address.

Since then I have been unable to send email using Thunderbird via the office Zimbra mail server that I administer. I have two-way communication with the mail server because I can receive email via Thunderbird with no problem and I can save messages to my Drafts folder and those messages are there when I open up the Zimbra webmail interface (from which of course I can then send the saved messages).

I have changed neither the Zimbra configuration nor my Thunderbird configuration. Everything used to work perfectly well before the router incident. My other colleagues continue to be able to send email from Thunderbird from their homes. So everything points to this being an issue with my router and/or cable modem.

When I attempt to send a message, the system times out after spending some time displaying the "Connecting to my.mail.server.com". I don't think that a connection is being made to the Zimbra server, although I can ping it from home with no problem. (I can't, however, telnet into it on port 25.)

Which log or logs should I examine on the server to see what might be causing the failed SMTP authentication? Would I have to enable more verbose logging in order to see the relevant reports?

If indeed I'm not even connecting to the server, what could possibly have gone wrong with the router and/or cable modem?

It's a puzzle. Thanks in advance for any words of wisdom you can offer.

Ed

[Bill Brock]

like your cable company has started blocking your port 25. If you are using Comcast and have a residential service I am pretty sure this to be the case. My Boss has a similar setup and must use Comcast's outgoing mail server to send while in Florida.

[EdMartin]

That's what it was. Without so much as a word of warning, Comcast is now blocking my outgoing port 25 traffic.

I have therefore set Zimbra to listen on port 587 as well as port 25 by uncommenting the statement

submission inet n - n - - smtpd

in /opt/zimbra/postfix/conf/master.cf.in

and restarting MTA

su - zimbra
zmmtactl stop
zmmtactl start

After reconfiguring Thunderbird to send outgoing SMTP traffic on port 587, everything is now hunky-dory at home.

Thanks for pointing me in the right direction.

Ed

[EdMartin]

Oh, and I should mention that I expect the above edit of master.cf.in will need to be redone each time I upgrade my Zimbra installation.