Blocking telnet to SMTP port

[Ed Wilts]

On Fri, Feb 27, 2004 at 10:13:20AM -0500, Adam Gilstrap wrote:
> I have seen some domains that prevent telnet access to port 25.  How can
> I implement this through iptables?

You can't.  If you block telnet access, then you're blocking all SMTP
traffic to that host.  The server has no way of telling that you're
using a telnet client instead of an MTA.

If you don't want to receive e-mail on that server, just shut
sendmail/postfix off.

-- 
Ed Wilts, Mounds View, MN, USA
mailto:ewilts at ewilts.org
Member #1, Red Hat Community Ambassador Program