using telnet to determine if smtp port 25 is open

Telnet Client: Windows XP
Telnet Server: Windows 2000 Advanced Server

Can I use the telnet client on my xp machine to determine if tcp port 25 is open on a telnet server (exchange Server)?

I tried, and here is what I get, even though the telnet server (exchange) is listening on port 25.

C:\>telnet 25
Connecting To not open a connection to host on port 25 : Connect failed

I thought I could do this, but somebody told me the following, and I am not sure if it is correct:
"MS supplied Telnet client to ports is not supported"

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From a command prompt in windows xp, you should be able to type:

telnet <servername or ip address>  25

If you get a 'can't connect' error, there is a connection problem.  Check firewalls etc.

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Matthew MillersCommented:
You can telnet to whatever port you like using the MS telnet client, the format you supplied is fine. - does this resolve to a internal address of external address?
If external, are you able to try this from a machine outside of your network - somewhere else on the internet?
Your server will not know the difference between your telnet attempts, and a connection from an SMTP mail server.  Check your PC's anti-virus or firewall software to see if outgoing port 25 is blocked.  It often is.
you can also do a telnet check from the server itself.
do like that : telnet 25
and if you get an answer your port is open and if not's not open.
don't mess with firewalls or rules do it from the mail server.
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