Exchange 5.5 SMTP Problems

I have just set up an Exchange server on NT running MS proxy 2.  I have configured the exchange server to listen on port 25 on the external network card.  I have also created a MX record on our Primary DNS server also running on the same mahcine.  However I am having problems receiving mail from the internet.  I can send mail fine just can't receive.  If i send to a recepient on the exchange server from say my hotmail account I get nothing.  No NDRs nothing.  If I send a message from our exchange server to hotmail then reply to it I get the message but in a weird way.  It shows up in my inbox as an attachment to a message from UUNET's mailer-daemon.  The message from uunet says unauthorized relay request.  How is UUNET getting my smtp mail.  They are our service provider but we run all of our own equipment with the exception of the leased dsl line from them.  Is is possible that they are filtering incoming smtp packets on the block of IP addresses that we received from them.  I can't figure this one out.  It is making me crazy.  
   Any light you could shed on the subject would be great.  Thank You.

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mjsmith99Connect With a Mentor Commented:
It sounds to me like the outside world thinks that your MX record points to your ISP.  

Are you sure that your server is the authoritative server for your domain ?

Check this at the following site to see where your MX record points, using the "dig" tool.

Enter you own domain name, and set the "type" to "Start of Authority (SOA)", and click "Query Name Server".

You should see your own server's IP address listed.

Verify that the MX record(s) for your domain point to the server.

Use the same site, but choose a "type" of "Mail Exchanger (MX)".  Again your should see your server's IP address listed.

If you still cant see the problem, you could try manually sending mail to your site.

Use a dial-up connection (to avoid any weird proxy effects), to an ISP (preferably not UUNET) and get Unix shell access.  Then type the command "telnet your_IP_address 25".

Your server should allow the connection and display a banner.  Type the following with suitable substitutions.








If this works, you have done exactly what an external sender would do, so external mail ought to succeed.

If the telnet connection succeeds (i.e. you get a banner from your server), you can probably exclude your ISP as a cause, and take a look at the settings on your Exchange server (e.g. the IMC routing tab).

Can you send mail manually from your LAN ? (using same telnet technique ?).  If not, the problem is definitely your server.


Sorry I cannot be more specific, but you need to gather more information.


Tim HolmanCommented:
Talk to your ISP - it sounds like they've disabled SMTP relay (to stop spam).
Is UUNET your ISP ?
goatranceAuthor Commented:

Thanks for your comment

UUNET is my ISP.  What I can't figure out is why it would be relaying through there server.  We have our own domain managed by our own name server.  My understanding of SMTP it should come right to us or get sent back.  Is that correct?


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goatranceAuthor Commented:
Thanks mjsmith.

I think you are on to somthing here.  I realized yesterday that it seems to be more of a DNS problem.  Either my NS is not working properly or INternic did not delagate authority to my nameserver.  I can telnet to the smtp port on the proxy and get a response.  I just can't do it by the 2nd level domain name.  However I did discover that if I use the name of my nameserver like I have no problem.  I am thinking that internic registered my domain as the name of my server.  Does this sound right?

Thanks again Aaron.
Tim HolmanCommented:
If you've registered with Internic, you should be able to pull your details from their server. I think.
Alternatively, post up your domain name and we'll look for you !
My money's on an incorrect MX record. You need to check where it is pointing.


goatranceAuthor Commented:

I figured out the problem.  It was a DNS problem.  I had to add a blank A name record to point to my name server then I could resolve my domain.  Thanks for your help.  I will give you the points since you were closest to the answer.

goatranceAuthor Commented:
This was the closest answer.  The answer was that I needed a blank A record in my MS DNS server pointing to my name server for it to resolve my second lever domain name.
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