Problem sending mail outbound but receiving them inbound 2

[vectorw16]

Hi every one,

I have a small problem with my mailserver but I don't know where to look to correct this !

I have problem sending mail to some company ...

I could say that 98% of my mail are going out without problem but some domain just plain don't pass ! Example

When I'm trying to send email to UQAM university in Montreal my e-mail bounce right away with this error (translation from french):


Impossible to reach bla bla bla ... :
'valid.address@uqam.ca' le 2004-03-02 09:53
Name of the recipient is not reconized
MTS Identifier of the original message is : c=CA;a= ;p=####;l=BOGUSERVER-040#######-5###


of course 'valid.address@uqam.ca' is not the true address but still it's really a valid address well spell and without error !

I can send an e-mail to this address with hotmail for example and it works so what's wrong with my mail server? I can't send e-mail to any @uqam.ca address ?

Last summer it was with another company any address @b2b2c.ca ??

Any idea ?
Thanks

 

[ReddLefty]

Could be your server is banned from UQAM o isr on a black list. Universities usually have up-to-date databases on Spam and Relay abuse IPs. Check with the following addresses and see if your server IP is on the list:

rbl.maps.vix.com
relays.mail-abuse.org

There is also a possiblity that UQAM uses reverse lookup on domains to prevent spoofing and your mail domain name is not properly registered.



"In space, nobody can hear you click..."

 

[vectorw16]

I would be supprised if I was posted on a black list I close my relay long ago and it's working fine on that side !

Where do I need to check to know if my mail domain is properly registered ?

Thanks for your help

 

[lushone]

are you sure that you can see there domain. have you tried to do an nslookup to there site. If that works can you ping them by hostname

 

[vectorw16]

Yes I can Nslookup uqam.ca and I can't ping them by hostname but this probably normal since many company (like us) doesn't allow ping on their address !

 

[rdroske]

Do a reverse dns lookup of your mail servers public IP address to see if it is resolving to a name in your domain.

If not many sites will reject you.

 

[vectorw16]

I've tried a reverse lookup on UQAM mailserver and it Worked

On my server it didn't !

http://remote.12dt.com/rns/

But I have a friend working in another company and reverse lookup doesn't pass on his address too!

Still he can send an e-mail to the address@uqam.ca ???

What would be the difference between him and me ?

 

[rdroske]

Probably means that it (reverse DNS) is not your problem in this case but I would get it to work anyways. You will definitely have a problem later with it.

Most likely this has to be done through your ISP (even if you are doing your own DNS) unless you happen to have a full Class C address Space.

As to other problem you'll have to debug from your exchange server.

MX lookup shows mail servers are mail.uqam.ca and mail2.uqam.ca

I can telnet to port 25 of both names and connect to an smtp server. Check that first.

Then ping both names and make sure the address they resolve to matches what a dns lookup says they should. Don't worry whether ping works just need to verify that both are resolving to the correct IP address.

 

[vectorw16]

Update :

I have put a syslog on my firewall to see what was happening when I send an email that bounce and here is the result :

03-26-2004 17:41:40 Local0.Info 192.168.#.# time="2004-03-26 17:41:41" fw=2##.###.###.### pri=6 c=1024 m=98 n=527472 src=192.168.#.#:1688:LAN dst=216.46.#.#:25:WAN proto=tcp/smtp rcvd=672

03-26-2004 17:41:34 Local0.Info 192.168.#.# time="2004-03-26 17:41:35" fw=2##.###.###.### pri=6 c=1024 m=98 n=527471 src=192.168.#.#:1680:LAN dst=216.46.#.#:25:WAN proto=tcp/smtp rcvd=672

As you can see it's the same message 2 times ! The only thing I can't figure out is rcvd=672 what does it means !

Normally when a e-mail is sent correctly I see :
03-26-2004 17:43:19 Local0.Info 192.168.#.# time="2004-03-26 17:43:20" fw=2##.###.###.### pri=6 c=1024 m=98 n=527481 src=192.168.#.#:1698:LAN dst=64.156.215.5:25:WAN proto=tcp/smtp sent=1294

You see sent= 1294 not received=672 !
This is Kiwi syslog !

Thanks

 

[vectorw16]

another thing I agreed with my isp to activate reverse lookup ! I'll keep you informed !

 

[vectorw16]

I consider the post closed !

It work I was black list at UQAM but it was a very old record probably before I close my relay 2 years ago !

+ the reverse lookup unlock a second adress that was block in another company !

Thanks everyone for your help !