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

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

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!

/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