Can't send email outside of our company.  Inbound is fine.  Need help fast!

Undeliverable reads:

Your message did not reach some or all of the intended recipients.

      Subject:      please reply 1101s
      Sent:      10/29/2009 11:02 AM

The following recipient(s) could not be reached:

      User Name on 10/29/2009 11:02 AM
            There was a SMTP communication problem with the recipient's email server.  Please contact your system administrator.
            <server.domain #5.5.0 smtp;554 Client host rejected: cannot find your hostname, [ip address]>
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Alan HardistyCo-OwnerCommented:
Sounds like your DNS MX record has an IP address instead of an FQDN e.g. mail.yourdomain.com.
If you can either post your domain name or check it on www.mxtoolbox.com and verify this is the case.
Alan HardistyCo-OwnerCommented:
Also please check to see if you have Reverse DNS pointer setup on http://www.mxtoolbox.com/diagnostic.aspx
If not - please call your ISP and get one setup asap.

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Alan HardistyCo-OwnerCommented:
xtrovertAuthor Commented:
Our ISP is a forwarder of our email.  Upon calling them, they discovered an issue with their forwarding IP being blacklisted.  It became a known issue to all their customers that used them as a forwarder.  Thanks for the help.
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