Topic: Cannot receive external email

[mudra]

I have done a search and I have tried to fault find, but I am at a complete loss. I cannot receive email from outside of my network

(A) I have checked that my Dyndns account is OK and that my dynamic IP is correct.
(B) I can ping my server and I can reach the webpage using the IP address stored in the Dyndns account
(C) I can send and receive email locally inside my network.
(D) I can send email externally
(E) I have tried rebooting to no effect.

I have tried the qpsmtpd.log file and I can see no errors. The bounced email has the following error:-

Sorry, I wasn't able to establish an SMTP connection. (#4.4.1)
I'm not going to try again; this message has been in the queue too long.

My SMESERVER is directly connected to my cablemodem, and I have not changed anything (that I know of) since yesterday when it worked fine.

Any thoughts where I should look next.

I am 99% certain that this is not a bug, but if anyone thinks I should start a bug I will.

Thanks

Mudra

[mercyh]

see if this tells you anything.

http://www.mxtoolbox.com/

click diagnostics on the second page for more information.

[mudra]

From page one at MX Lookup Tool - I receive the following information:-

ns3.dyndns.org did not respond with MX records for 'holloway.homelinux.com'

A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond xxx.xxx.xxx.xxx:25

This is the reply from the MX Lookup Tool Diagnostics. The IP is the one reported by my DYNDNS.com account.

What does the above mean ? Is my mail server disabled ? How do I re-enable it, if it is ?

Thanks for any help.

James

[mercyh]

So you are saying that the first screen returns an MX record something like this:

Preference   Host Name           IP Address                   TTL    
0        mail.MyDomainName.org     xx.xxx.xxx.xxx              7200

Then when you press the diagnostics button you get the following

A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond xxx.xxx.xxx.xxx:25

correct?

-------------------------------

If the above is correct several things could be happening.

1. Your ISP is blocking port 25.
2. DYDNS is not forwarding port 25 to your server correctly. (I don't use DYDNS and am not sure how it works)
3. Some of your e-mail services are stopped on the server.
4. ????

[mercyh]

Ah,

I beat your edit. It sounds to me like your MX record with DYDNS is messed up.

[mudra]

If I put my IP address into the diagnostic for the MX TOOL diagnostic I get the same error. Can I check that my email server is switched on correctly ?

Thanks for all your help.

[mercyh]

If you want to test directly with your IP address you need to use this location:

http://www.mxtoolbox.com/diagnostic.aspx

You may have a problem with your server but that will not throw the following error. (the DNS system should return a record even if a server at that IP address does not exist)

This error is irrelevant to if YOUR server is working or not:

ns3.dyndns.org did not respond with MX records for 'holloway.homelinux.com'

You will not be able to send mail from the WAN to @holloway.homelinux.com until this is resolved.

[mudra]

I looked this up on Dyndns.com

Do I need MX records for my domain?

Technically, a domain does not require MX records to receive email. By default, a sending mail server should attempt to deliver mail to the host itself if no MX record is present. For example, if a sending server is trying to deliver mail to user@domain.com, and domain.com has no MX records, it will try connecting to any mail server at domain.com itself.

I have built another server, out of some spare parts and an old harddrive and put 7.4 on it (clean), this will send and receive email with the dyndns record as is !?!?!

I am pretty certain that I must have borked my "original" install somehow.

I will have to sort this out tomorrow.

Thanks for all the help.

[mercyh]

interesting....

it seems I learn things here avery day.

[Craig Cabrey]

Is the server a gateway or just in server mode?

If its the latter, make sure all ports are correctly forwarded.

[mercyh]

Craig Cabrey,
Did you see this:

My SMESERVER is directly connected to my cablemodem,

mudra,

If you want to test directly with your IP address you need to use this location:

http://www.mxtoolbox.com/diagnostic.aspx

This test run with your external IP address should tell you if your mail server is working correctly (or if your ISP has blocked port 25). Run it against the original server and then against the "test" server you have built and see if the results are the same.

As far as the need for an MX record, I cannot say it wouldn't work without one. I have never tried it. It seems like if it works with dyndns that it would be something they are doing to make it work. When I think of all the hoops I have jumped through to make sure that all mail can get through without hitting any blacklists or RFC compliance issues, it seems that it could not work with no MX record at all..............

[Craig Cabrey]

Ahh, I did not, sorry about that.

Well it could possibly be SME's internal firewall. Unlikely, but unless a configuration file was messed with...

[F22-Raptor]

Make sure your ISP is not blocking port 25, the test using the IP will tell you that.
If that is the case DynDNS has a serivice called MailHop or someting like that for about $30/year.
Once enabled it can forward mail to any port on your system, at this point you can configure the firewall on your system to forward traffic on say port 2525 to port 25 on local machine or if your mail server is behind the firewall then to port 25 of your mail server.

D.

[CharlieBrady]

(A) I have checked that my Dyndns account is OK and that my dynamic IP is correct.

I doubt it. Your server doesn't seem to be reachable.

[CharlieBrady]

For example, if a sending server is trying to deliver mail to user@domain.com, and domain.com has no MX records, it will try connecting to any mail server at domain.com itself.

No, that is not true. "any mail server at domain.com" has no meaning. If there is no MX record for domain.com, then it will use the A record for domain.com, if one exists. So an A record for domain.com is all that is required.