What is my mail server's IP address?

Every once in a while, I'll send an email to a client of mine with Yahoo email and I receive an error message. The error message is below. What I found out is that I have to report it to Yahoo and they may clear me. Not sure how long this will take or even if it will work, so I'll find out soon enough.

So, to file the complaint, I was sent to this Yahoo address for 421 errors: http://help.yahoo.com/help/us/mail/defer/defer-06.html

Once there, I filled out some information, mostly about the email. But, one thing hung me up for a little while. How to get my mail server's IP address. It only took a minute, so here's how to get your mail server's IP address.

1. In Windows, click on Start | run
2. Type in the text cmd then click on the OK button.
3. You should now see a small black window with white text.
4. In that box, type in ping mail.yourdomainname.com (fill in yourdomainname.com with your domain name)
5. Hit enter
6. If this works, you will see the IP address of your mail server.
7. To close the window, type in the words exit, then hit enter.



Here's the error message:
Could not deliver message to the following recipient(s):

Failed Recipient: xyz@yahoo.com
Reason: Remote host said: 421 Message from (xyz) temporarily deferred - 4.16.50. Please refer to http://help.yahoo.com/help/us/mail/defer/defer-06.html

-- The header and top 20 lines of the message follows --

Received: from IMAIL2 [1.1.1.1] by x.x.x with SMTP;
Wed, 12 Mar 2008 07:21:52 -0500
Received: from syx [1.1.1.1] by x.x.x with ESMTP
(SMTPD-8.22) id AB9C0D58; Wed, 12 Mar 2008 06:16:44 -0500
From: "person a"
To: "'person b'"
References: <010401c8839a$1f5b2b90$5e1182b0$@bailey@bluecreekweb.com> <551043.95195.qm@web53004.mail.re2.yahoo.com>
In-Reply-To: <551043.95195.qm@web53004.mail.re2.yahoo.com>
Subject: RE: New Order
Date: Wed, 12 Mar 2008 07:16:43 -0400
Message-ID: <000001c88432$8dfe1790$a9fa46b0$@bailey@bluecreekweb.com>
MIME-Version: 1.0
Content-Type: multipart/alternative;
boundary="----=_NextPart_000_0001_01C88411.06EC7790"
X-Mailer: Microsoft Office Outlook 12.0
Thread-Index: AciDoLveNFKaJDfJSpGamAweiCoPMgAkcCdg
Content-Language: en-us
X-Declude-Sender: joe.bailey@bluecreekweb.com [97.80.142.6]
X-Declude-Spoolname: Dbb9c02210000d12b.smd
X-Declude-RefID:
X-Note: Outgoing Scanned by IMail.GlobalWeb.net 4.3.64
X-Scan: Score [0] at 06:16:52 on 12 Mar 2008
X-Fail: Whitelisted
X-Country-Chain:

This is a multipart message in MIME format.