Geek Pop Quiz.

[theweaselking]

I have a Ubuntu 6.06 server.

I want all tcp connections to port *X* on the server to automatically be seamlessly and quietly redirected to port *Y* on that very same server. And, obviously, the responses need to go back to the original host on that port. However, normal connections directly to port *Y* should not be affected.

I also want this change to be server-side only. No router changes, no nothing.

How can I do it?

EDIT: zastrazzi came through with the correct wording of iptables I needed, and now I see my error. Yay!

Comments

[zastrazzi.livejournal.com]

To redirect port 80 to 8080 use:

iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 8080

[theweaselking.livejournal.com]

There we go. I was trying to redirect to localhost:Y, and it was breaking things.

Problem solved! Thanks.

[zastrazzi.livejournal.com]

No problem. It was mostly knowing what to google and recognizing the result :)

[theweaselking.livejournal.com]

I was googling, but all my results were for forwarding to a different machine, and the server did not like that.

And don't undervalue the ability to google *and* comprehend. It's important!

[jsbowden.livejournal.com]

Comprehension is over rated.

[rbarclay.livejournal.com]

iptables, bah. Far too elegant a solution. Real Geeks(tm)'d do it with netcat and inetd ;)

[theweaselking.livejournal.com]

I was open to any solution. I just was figuring iptables made the most sense, and was discovering that I couldn't make the fucking thing do what I wanted.

It's because I didn't have --to-port. I was just trying to redirect to localhost:Y and that was causing issues with the server process.