how to stop using *telnet <domain> 25*

[Gary]

On Sat, Jan 24, 2004 at 12:00:15PM -0600 or thereabouts, Gary wrote:
  
> If they are using port 25, and you have an MTA running, sendmail, postfix,
> or qmail.  You should set your MTA to allow use for only your existing
> internal IP range, and you will not have this problem.. They will not be
> able to send mail period. 
> 
> In short, you have not properly closed down your MTA, and you are an open relay. 

to further expand this.. it is unclear to me whether the original writer
was concerned about someone just telneting into his machine, or whether
they were actually sending mail... This problem report was not clearly
defined. 

Check your mail logs, are they sending? If so, do the above, as you are an
open relay, and will be found.  

If they are not sending, and you are just seeing telnet entries, well,
that is no big deal.. anyone in the world can telnet into any SMTP mail
server... you can do it to Yahoo, MSN, anyone, any server, anywhere. That
is the nature of the SMTP protocol... it is no big deal. The trick is to
properly configure your MTA so that only authorized parties can send
mail.. 
 

-- 
Gary