SMTP spoofing ?

Thu Feb 19 18:52:16 UTC 1998

In article <Pine.BSI.3.91.980219115057.13529A-100000 at ivan.iecc.com>,
John R Levine  <johnl at iecc.com> wrote:
>Are there any routers currently available that can do port 25 spoofing for
>dialup users?  That is, when the user attempts to connect to port 25
>anywhere, he in fact connects to port 25 on your own SMTP server instead. 

Cisco? Just setup a routemap with an access list that matches TCP port
25, and sets next-hop to a box that supports `transparent proxying'.
Linux does, and AFAIK the *BSD's can do it as well.

Some squid users are doing this with port 80 to redirect HTTP traffic
through the caching proxy - there's some docs for it on http://squid.nlanr.net/
in the FAQ, read the section about "transparent proxying".

However I think that policy routing is still process switched, and as
such can use a lot of CPU on the router.

Mike.
-- 
 Miquel van Smoorenburg |  The dyslexic, agnostic, insomniac lay in his bed
    miquels at cistron.nl  |  awake all night wondering if there is a doG