Hi,

I'm a newbie and have got Postfix/Dovecot working receiving email and sending email using Virtualmin's interface. I have Outlook pulling email from the mail server.

What's not working is sending email from Outlook to the email server then out to its recipient. Outlook times out. So does telnet.

I'm using Virtualmin to manage about 15 domains, low traffic stuff, and some of these need email accounts.

I have no clue where to begin to debug this sort of problem. Could someone suggest which files to look at, what is most likely the issue?

Thanks!

My first guess would be that the Internet connection the Outlook server is sitting on is blocking outbound traffic on port 25. You'll need to tell Postfix to listen on a secondary port to get around that. If you have TLS & authentication working, you can open the submission port (587) otherwise just add a second SMTP listener on something like port 2525 and point Outlook at that.

--James

My Outlook is a standalone, no server, behind a simple wireless router, sucking on a standard cable internet line. I have half a dozen email accounts that send/receive through Outlook no worries through mail servers on shared hosting servers. This issue is just with the Linode I've set up, with Postfix/Dovecot. And only with sending from Outlook. Everything else works fine.

Also, I'm running Ubuntu Heron (8.04), if that's important.

Also, how and where do I get Postfix to listen to any specific port? One of the config files has a listen value set to *. In rooting around the net, I saw other more explicit ways to set the value but they crashed my mail server so I set it back to the asterisk.

Thanks in advance for any ideas/direction.

I read Outlook as Exchange so I thought you were trying to use your Linode as a smart host for your Exchange server. My brain seems to not be working correctly today.

My guess at the problem would still have been the same however. To get Postfix to listen on alternate ports, have a look in the /etc/postfix/master.cf file. There is a line there that look like:

smtp      inet  n       -       n       -       -       smtpd

That's the line that tells postfix to listen on the smtp port (25) with the smtpd daemon. There is usually also a submission line which is commented out. You can uncomment that, restart postfix and give it a try--don't forget to tell Outlook to use the alternate port.

If using a different port doesn't work there is something very strange going on and you will need to do more troubleshooting. I would suggest at that point coming into the IRC channel to ask as it will be easier to work interactively.

--James

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Two answers, one if all mail clients are affected, one if it's only Outlook.

All clients affected:
In order to not act as an open relay, most Postfix installations only relay mail for hosts that are identified by the 'mynetworks' and 'mynetworks_style' parameters in the Postfix main.cf file, or hosts that are authenticated in some way (usually SASL).

My guess is that some part of this is not set up correctly so Postfix is just ignoring the connection from your home machine.

Take care when changing the value of mynetworks - getting it wrong can enable all your ISPs customers or, worse still the world, to relay through your Linode. Better to get SASL working - Postfix howto is here, not sure how Virtualmin deals with this, but the howto will let you check what's going on.

Only Outlook affected:
Some versions of Outlook implement an obsolete version of the SMTP AUTH command. In this case, you need to set the Postfix main.cf parameter 'broken_sasl_auth_clients' to yes. The default is no and the parameter probably isn't even in the file.

_________________
/ Peter

Thanks, Peter, for the detailed feedback!

In looking through the postfix and dovecot .conf files, using your pointers and the Postfix URL you include, I didn't really find any anomalies. For example, in Dovecot, the auth default, the socket listen conditional, right above the client definition was a line, user = root. I removed that, the same problem applied (send/receive from server, receive from Outlook, no send from Outlook through server). And my broken_sasl_auth_clients was present and set to yes.

What does seem odd is that my postfix conf file does not have mynetworks and mynetworks_style explictly set. When I type postconf -d at the command line, I see default settings which appear to limit the server to its subnet:

mynetworks = 127.0.0.0/8 75.127.97.0/24
mynetworks_style = subnet

In looking at the Postfix documentation, I can't tell what is the proper setting to allow me to send email from home, from really any location, as I do with other email addresses run through remote hosted mail servers.

If it would help to publish here the postconf output, let me know.

If you cannot telnet to port 25 on your linode from your Windows machine, it's most certainly your ISP preventing it. It's very common for ISPs to block port 25, except to their own mail server. Mine does that (Cablevision - a.k.a. Optimum Online).

If you don't want to mess with your mail setup, you can use iptables to forward, say, 2525 -> 25. Then config your Outlook to use 2525.

Actually some of my email accounts use port 25 and Outlook has no problem pulling from that port. So far.

The real issue I'm trying to solve, for now, is how to set the mynetworks values Peter mentioned above, how to explicitly set them to accept remote calls for email. Without making the mail server an open relay for spammers.

Any ideas what values to use for mynetwork settings?

And thanks James for the details on how to get Postfix to listen on other ports. If/when I get to that bit, it helps.

Thank you!

Port 25 is SMTP. Outlook would never "pull" (POP/IMAP) from that port. Again, can you telnet to port 25?

You don't want to use mynetworks to do this, since you said you want to be able to send from a variety of addresses. What you want is to setup SMTP AUTH access. See
http://postfix.state-of-mind.de/patrick ... /smtpauth/

If you really only need access from a single IP (or small range), you just add the address and mask to mynetworks, seperated by spaces.

_________________
The irony is that Bill Gates claims to be making a stable operating system and Linus Torvalds claims to be trying to take over the world.
-- seen on the net

Actually "pull" is the wrong word. I meant "get" in that I really don't know how email arrives, only that port 25 appears in use for some of my email accounts.

I can't telnet to port 25 for the mail server address. I think that is the root problem in that Outlook cannot "get" email from the server, again not knowing exactly how the mail is transferred. I'm a newbie to all this, hoping to learn.

Thanks for the lead to SMTP AUTH. Let's hope that works.

lookOut (and almost every other client) download mail using IMAP or POP3, and send mail using SMTP.

In case someone comes along with the same or similar problem, the issue turned out to be a combination of configuring SMTP AUTH and opening a port other than 25 (which my ISP blocks, I discovered as a result of this thread).

Thanks for everyone's help!