Re: redirect 127.0.0.1:25 -> 127.0.0.1:2000

[Alex Tang <altitude@funkware.com>]

In looking through the mail archive, i see this post:


Alex Tang wrote:
> Hi folks.
>
> I'm using a nat PREROUTING rule to forward all connections from port 
> 25 to port 2000.  This works fine for all addresses except for localhost.
>
> the rule i'm using is: "-A PREROUTING -p tcp -m tcp --dport 25 -j 
> REDIRECT --to-ports 2000" (CentOS4, kernel 2.6.9-55, iptables-1.2.11)
>
> For example, on my machine: foobar.example.com
>
> If i telnet from any machine other than foobar.example.com to 
> foobar.example.com:25, the connection is redirected  properly to 
> foobar.example.com:2000.
> However, if i telnet from foobar.example.com to localhost:25, i get a 
> connection refused.
> Telnetting to from foobar.example.com to localhost:2000 works fine (as 
> expected)
>
> Telnetting from foobar.example.com to foobar.example.com:25 also does 
> not work.
>
> I know that you can't do prerouting from localhost -> some.other.host 
> (or vice versa), but i thought localhost->localhost would work.
>
> Am i screwing up the rule? Should I add another rule?  Or am i just SOL.
>
> Thanks.
>
> ...alex...
>
>