claude

Member
Jan 13, 2005
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I have a client on my cPanel server that uses an Exchange email server at his company for mail. So I fixed the mx record on my server to point to his exchange server for mail. My question is: Since he uses qwest for the exchange mail server's internet connection, I need to call qwest to setup a reverse dns entry. Do I have them set it up as mail.domain.com or just domain.com?

Currently, he is able to send and receive mail with the exception of sending to the big boys like AOL and Comcast and DNS reports shows no PTR. Sending to AOL and comcast returns a " Unable to deliver the message due to a communications failure" error.

thanks, Claude
 

adept2003

Well-Known Member
Aug 11, 2003
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~ "/(extra|special)/data"
You should set it as mail.domain.com, assuming the Exchange server's hostname is mail.domain.com.

This may help to explain why...

http://www.desknow.com/kb/idx/4/025/article/ said:
Imagine that a mail server with IP address 101.34.123.12 connects to DeskNow via SMTP to deliver a message.

Following the SMTP protocol, it must introduce itself by saying 'HELO nexus.domain.com' where nexus.domain.com is its name (for example). If the "Reject message if reverse PTR record does not match HELO host" option is enabled in DeskNow, DeskNow will query the reverse DNS system to find out what is the name of the server associated to the IP address 101.34.123.12 .

If it is not 'nexus.domain.com' (example), then DeskNow assumes that the server is lying about its name, and rejects the message. This is, for insance, what AOL does. This causes many problems to a lot of inexperienced system administrators, because the reverse DNS issue is not very well known.
Although the above description is for a particular app, it pretty much summarises the process common across most apps.
 
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claude

Member
Jan 13, 2005
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Thanks very much for the reply.

As it stands, the Exchange mail server has a different name than the actual domain name.
domain name is: tddc-tec.com
Exchange mail server HELO name is: serverx.tddc.com

I'm confused on how this works as the serverx.tddc.com is not our true domain name, just a Windows Active Directory name. In fact, serverx.tddc.com and just tddc.com are some other persons domain names and have nothing to do with us.

So if I ask Qwest to set the PTR to serverx.tddc.com, which is OUR email servers name, it should work?

I'm a little slow, forgot my helmet at home and have experienced 5 head injuries today alone. :rolleyes:

Thanks for all of the help, -C