Telnet port 25 to an SBS 2003 from Vista or Server 2008 fails.

I am attempting to troubleshoot an email problem. Our company is trying to send to another company and the email will stay in the Exchange queue and we will receive a delivery delayed notification from our exchange server.

- We have a Exchange 2007.
- The destination email is Exchange 2003 Sp2, with a firebox as their router.
- I have tested email to their location from yahoo and other domains - these were successful.

I was following instructions on testing telnet to port 25 and have determined that I can telnet to port 25 on the destination from an XP or 2003 server, but I cannot telnet to port 25 from a Vista or 2008 Server.

Any insight as to why the telnet in these cases fail?
Any thoughts on why we may be receiving the delivery notification delayed?

Thanks much!!!
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mmack12Connect With a Mentor Author Commented:
OK, so it turned out to be the Firebox was causing the issue. It had an SMTP proxy turned on. Once I removed that policy and waited about 2 minutes I am now able to email and Telnet port 25.

These 2 links had similiar problems.
Rajith EnchiparambilOffice 365 & Exchange ArchitectCommented:
Are you blacklisted? Or they may have greylisting enabled?
mmack12Author Commented:
We are not blacklisted. Additionally, we are able to telnet to port 25 from an XP machine & a Server 2003 machine on the same network.
mmack12Author Commented:
I am now seeing the following error in the firebox logs:

SM: policy="svc:24" src_ip="x.x.x.x" dst_ip="x.x.x.x" pr="tcp" src_port="24259" dst_port="25" src_intf="2" dst_intf="12" rc="590" msg="Connect timeout" proxy_act="svc:24"
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