Thanks Hal!

[Brian Kelsay]

Gerald Combs wrote:

> Brian Kelsay wrote:
> 
>>Gerald Combs wrote:
>>
>>
>>>bam:/home/gerald> telnet kclug.org 25
>>>Trying 139.146.133.42...
>>>Connected to kclug.org.
>>>Escape character is '^]'.
>>>220 kclug.org ESMTP Postfix (Debian/GNU)
>>>quit
>>>221 Bye
>>>Connection closed by foreign host.
>>
>>
>>Umm, why is telnet running/responding on the server?
> 
> 
> I'm not sure if telnet is running on the server, but Postfix is
> responding on port 25.  Most telnet clients allow you to specify a port
> number after the host name.  If you specify a non-standard port from
> Telnet's perspective (not 23), the telnet client just opens a direct
> ("raw") connection (normally it tries to exchange environment
> information upon connecting).  At this point you're just pushing bytes
> at the server, like any other TCP client.  Since a bunch of popular TCP
> protocols are text-based, this means you can interact with the server
> manually.
> 
> This has several uses, including the ability to apply Occam's razor in a
> troubleshooting situation.  If someone is having trouble connecting to a
> web server, you can run

Sorry, I didn't get a good look at the port.


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Somewhere there is a village missing an idiot.