How to I bounce/redirect packets from one external ip to another?

How to I bounce/redirect packets from one external ip to another?

[Markus Wells]

  I'm travelling and I want to access my news server remotely. They have 
it set up so that it will only accept connections originating from my 
home ip, so I was hoping one of you packet mangling gurus might have a 
couple lines of code so that I can redirect nntp traffic from an 
arbitrary external ip to another external ip(the news server) via my 
home firewall.

  Thank you for any help you can offer!

Markus

Re: How to I bounce/redirect packets from one external ip to another?

[Markus Wells]

  Thank you for the advice, but here's what I ended up doing and it 
worked, although I definitely have to say that your solution is more 
secure. But as it is forwarding to my isp's news provider's server, I 
just don't care....   :D

Here's what I did:

/usr/sbin/iptables -t nat -A PREROUTING  -p tcp -d <my outside ip> 
--destination-port nntp -j DNAT --to-destination 216.168.3.44:119
iptables -t nat -A POSTROUTING -p tcp --dst 216.168.3.44 --dport 119 -j 
SNAT --to-source $WAN_IP
/usr/sbin/iptables -A FORWARD -p tcp -d 216.168.3.44  --dport 119 -j ACCEPT

  When I get a chance I'll restrict the access to it with the -s switch, 
but as my house just had an electrical fire, I'm just not terribly 
worried about it!


Thanks for the feedback!


Robb Bossley wrote:
> If you open up (or use port knocking) to access your home firewall ssh
> port and us# forward 1234 (nntp)
/usr/sbin/iptables -t nat -A PREROUTING  -p tcp -d 206.124.144.176 
--destination-port nntp -j DNAT --to-destination 216.168.3.44:119
iptables -t nat -A POSTROUTING -p tcp --dst 216.168.3.44 --dport 119 -j 
SNAT --to-source $WAN_IP
/usr/sbin/iptables -A FORWARD -p tcp -d 216.168.3.44  --dport 119 -j ACCEPT

e an ssh tunnel from wherever you are logged in to your
> home firewall, you might be able to do it.  Something like "ssh -L
> <localport>:<hostip>:<hostport> <ipaddress>" .  Just fill in the
> blanks.
> 
> This assumes that your home firewall is running sshd, of course.
> 
> 
> 
> On 2/6/06, Markus Wells <markus@wiztech.cc> wrote:
> 
>>  I'm travelling and I want to access my news server remotely. They have
>>it set up so that it will only accept connections originating from my
>>home ip, so I was hoping one of you packet mangling gurus might have a
>>couple lines of code so that I can redirect nntp traffic from an
>>arbitrary external ip to another external ip(the news server) via my
>>home firewall.
>>
>>  Thank you for any help you can offer!
>>
>>Markus
>>
>>