Re: anybody else been spammed by "no-ip.com" yet?

[Marc MERLIN <marc_news () valinux com>]

On Fri, May 10, 2002 at 11:27:10AM +1000, Terence Giufre-Sweetser wrote:
> Now there's a good idea, and it works, I have several sites running a
> "port 25" trap to stop smtp abuse.
>
> To stop port 25 abuse at some schools, the firewall grabs all outgoing
> port 25 connections from !"the mail server", and to !"the mail server",
> and runs then via "the mail server", which stops header forging, mass rcpt
> to: abuse, and vrfy/expn probing. Anything that goes past the filters has
> a nice clear and traceable received by: line.

I'm not sure what's so swell with this.
I require  SMTP AUTH  over SSL  with STARTTLS  (exclusively), and  this nice
little hijack scheme makes for great support calls.

They  steal the  SMTP connection,  and then  are enable  to provide  the SSL
connection and our server certificate (obviously), so the connection fails.

Yes, the  "solution" is to pick  a different non standard  port, which comes
with its own set  of problems (not counting mail clients  that are unable to
use a different port), but I'd much rather that they do not hijack my client
connections  (blocking open  relays  and  DUL IPs  works  just  fine if  you
choose/need to do that)

Marc
-- 
Microsoft is to operating systems & security ....
                                      .... what McDonalds is to gourmet cooking
  
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