Mail server test (Sprint rejecting mail)

http://www.webhostingtalk.com/showpost.php?p=3827450&postcount=5

[QUOTE=SPaReK;3827450]From the shell of your server try doing the following:

[code]dig sbcglobal.com MX[/code]

This will show you the MX records for sbcglobal.com, what servers mail would go to for this domain. It may show the IPs of these mail servers (if there are multiple MX records listed, just pick one). If it doesn't, perform a DNS lookup on that MX record

[code]host [/code]

Actually, when I did an MX lookup on sbcglobal.com, I didn't get anything back. Perhaps they are not using MX records. I believe if no MX records are listed, then mail servers will go to a domain's A record and attempt to use that to send mail to, so just do a:

[code]dig sbcglobal.com A[/code]

which should give you an IP address that sbcglobal.com resolves to, again if multiple ones are listed (I see two), just pick one. If you feel frisky, you can perform this for each IP address listed.

Once you have the IP address, connect to it on port 25:

[code]telnet 25[/code]

You should get connected to their mail server, you'll probably see an introduction banner, now introduce yourself:

[code]EHLO [/code]

where is the name of your server. Now issue the following commands:

[code]mail from: >
rcpt to:
DATA
From: postmaster@
To: customers-isp-account-where-mail-should-forward-to@sbcglobal.com
Subject: Test Message

Test Message
.
quit[/code]

Notice that the e-mail addresses in mail from and rcpt to should be enclosed in <'s and >'s. Some mail servers will work without these, some won't. I believe its proper standard to include these, but someone can correct me if I'm wrong. Also, its important that postmaster@ represent a real e-mail address. I just made this one up, since you should have this set up on your server, but if you don't any e-mail address will work. Also notice the blank line after Subject and Test Message. This empty line is necessary to signal, this is the end of the headers, the message follows. The period on its own line tells the server that the message is done and quit just disconnects you from their mail server.

That message should go through without any problems. If you see any errors in a particular step, then it may lead you to where the issue is.

Hope this helps.[/QUOTE]