Exim sends email but unable to recieve.

M

modem

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Apr 7, 2004
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I had an issue pop up this morning with Exim... or which I think is with Exim. For months now Exim has been working flawlessly to send and receive email. I have the firewall properly configured, have spam assassin 2.63 installed that comes with the latest 1.22.4 DA script.

Anyway this morning I recieved my usual 100 or so emails only to discover that the ones I had sent... were still in my Outlook inbox with outlook giving the following error:

'Outlook is unable to connect to your outgoing (SMTP) mail server...'

So I started checking a few things. I ping the server and that works. POP3 works just fine as I receive all of my mail. I also checked the SMTP servers for other domains and they too can not send email via SMTP either.

At this time I then went to the Exim Que, cleaned out 3 backlogged messages, restarted Exim to no avail. I still get email but Outlook gives the message that it can not send email because it can't contact the smtp server.

Any ideas???
 
Have you done an nslookup on the name your client thinks is your mailserver, to see if it resolves?

If it resolves, then try to connect to it on port 25 using telnet, and see what you get.

How you do that is OS and telnet client dependent; on my linux desktop I do:

$ telnet example.com 25

Do you get connected?

Jeff
 
Yes I have, that was the first thing I checked. I use the same domain name for both pop3 and smtp email (mail.modemnet.org), and it resolves just fine. I have had telnet turned off and use SSH only on the server along with the firewall to accept connections on port 25 for email.

This setup has worked without issue since the server went in place back in March. Just to rule out items, I upgraded from Exim 4.32 to DA's Exim 4.34-1, restarted the server, stopped and restarted exim along with vm-pop3d. POP3 isn't the issue because I can recieve email just fine and when i stopped that process I got an error in Outlook telling me the POP3 servercould not be contacted (good. because I restarted that and it worked.)

Any other ideas? Email has been working flawlessly till this morning. Actually brb I just had an idea.


jlasman said:
Have you done an nslookup on the name your client thinks is your mailserver, to see if it resolves?

If it resolves, then try to connect to it on port 25 using telnet, and see what you get.

How you do that is OS and telnet client dependent; on my linux desktop I do:

$ telnet example.com 25

Do you get connected?

Jeff
Click to expand...
 
I *thought* the issue might have had something to do with me making a DSL router change last night but I put everything back to regular settings and still nothing changed. It's still saying that the outgoing mail server can't be contacted. I tried on various PC's with other clients like Mozilla Thunderbird and they all give an SMTP server error message of sorts.

So far this is what I've done:

- Verified it's not any home PC just not seeing the server
- Changed routers here at home.
- Checked and make sure nslookup works for the domain.
- Rebooted the server.
- Restarted the Exim service
- Upgraded Exim from 4.32 to 4.34-1
- Tried sending mail on a different domain/same server. (same issue)
- Stopped SpamAssassin and POP3 to test. No problems there.
- Checked the iptables settings to make sure port 25 was open. It is.
- Checked the rest of iptables for no other errors. There were none.

Any ideas at this point?? I have literally no idea why Exim just stopped allowing me to send out emails. It's blown my mind.
 
I don't believe it's exim. I have no trouble connecting:

[jeff@of1 jeff]$ telnet 192.216.133.217
Trying 192.216.133.217...
telnet: connect to address 192.216.133.217: Connection refused
[jeff@of1 jeff]$ telnet 192.216.133.217 25
Trying 192.216.133.217...
Connected to 192.216.133.217.
Escape character is '^]'.
220 stargatesg1.modemnet.biz ESMTP Exim 4.34 Wed, 01 Sep 2004 16:41:03 -0400
quit
221 stargatesg1.modemnet.biz closing connection
Connection closed by foreign host.
[jeff@of1 jeff]$

My guess is that your connectivity ISP may have started blocking port 25 traffic.

Check with your ISP.

Jeff
 
Unfortunately you were right. I checked and as of this morning they quietly activated port blocking on various ports to help control virus/trojan/worms from spreading. They are blocking or limiting the following ports:

25, 135, 137, 138, 139, 445, 1025.

Now I have to figure out how to handle this since I have hosting customers who use the same ISP as me for access, but use me for hosting and my mail server.

Any suggestions on getting around this or when it comes dealing with Frontiernet.net?



jlasman said:
I don't believe it's exim. I have no trouble connecting:

[jeff@of1 jeff]$ telnet 192.216.133.217
Trying 192.216.133.217...
telnet: connect to address 192.216.133.217: Connection refused
[jeff@of1 jeff]$ telnet 192.216.133.217 25
Trying 192.216.133.217...
Connected to 192.216.133.217.
Escape character is '^]'.
220 stargatesg1.modemnet.biz ESMTP Exim 4.34 Wed, 01 Sep 2004 16:41:03 -0400
quit
221 stargatesg1.modemnet.biz closing connection
Connection closed by foreign host.
[jeff@of1 jeff]$

My guess is that your connectivity ISP may have started blocking port 25 traffic.

Check with your ISP.

Jeff
Click to expand...
 
You've got several options:

1) learn to live with it. You can use your ISP's outgoing mailserver, and so can your customers. In fact, they probably should. If frontiernet.net is one of those misguided ISPs that won't let you use your own domain in a return address if you use their mailserver, then this option won't work for you.

2) if frontiernet.net has given you a static IP connection to the net, then you should talk to one of their tier-two support reps, and try to get them to make an exception for you, since you're in the business and need to use your own mailserver. They may just tell you, "too bad", but you won't know unless you ask. Of course this option may not work for your customers.

3) find another ISP; one that will allow connections on port 25.

4) Set up your exim.conf file to support authenticated smtp on port 587 (note that neither the original exim.conf file suplied originally by DA, nor the new one they're supplying with the latest exim (and which I wrote and also distribute here support port 587 by default).

You can find more information on using port 587 here; search for "I'm an ISP. What should I keep in mind?".

Jeff
 
Hey,

Take a look at frontiernet.net's website and at the top of the page there is a link that will tell you what they did and why...

David
 
Yeah I know why they did that and thats understandable. But that will affect businesses who have webhosting and websites meaning it will disrupt alot of legtimate email and cause alot of PC illiterate computer customers to go in a panic.

I was thinking earlier... is there a way to have Exim run on two ports? For example port 25 would remain standard, but for those customers of mine who are behind isp's who block port 25, is there anyway to have Exim use 25 and say 2525? Or something to that affect??
 
Did you read my reply? 587 is the port to use.

And there's information all over the Internet, including at the spf.pobox.com site I mentioned.

Jeff
 
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