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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 outbound.fakemailservertest.net 25
Connecting To outbound.absmailgateway.net...Could 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"

Thanks
Cliff

ASKER CERTIFIED SOLUTION

Daryl Ponting

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Matthew Millers

You can telnet to whatever port you like using the MS telnet client, the format you supplied is fine.

outbound.fakemailservertest.net - 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?

LeeDerbyshire

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.

jubai74

you can also do a telnet check from the server itself.
do like that : telnet 127.0.0.1 25
and if you get an answer your port is open and if not .....it's not open.
don't mess with firewalls or rules do it from the mail server.