Port redirection, iptables, apache questions?

sarajevo · 09-19-2006, 10:35 AM

Hi all,

I have following situation
comp_A(80.xxx.xxx.xxx)--------crossover-----comp_B (192.168.1.20)
On comp_A I have a rule
iptables -t nat -A OUTPUT -s any/0 -d 80.xxx.xxx.xxx -p tcp --dport 80 -j DNAT --to-destination 192.168.1.20
And when I enter at web browser on comp_A 80.xxx.xxx.xxx I got apache test page served on comp_b.
When I at comp_B change port server listens from default 80 to another, let say 100, and on comp_A change rule to
iptables -t nat -A OUTPUT -s any/0 -d 80.65.170.142 -p tcp --dport 80 -j DNAT --to-destination 192.168.1.20:100 and then refresh page on comp_A I cannot get same result as before. I got
Not Found
The requested URL / was not found on this server.
Apache Server at 80.xxx.xxx.xxx Port 80

With iptables rules I redirected all http request to comp_B.
In first case everything is ok, but why this does not work ( serve me the same apache test page ) when I change port number apache listens on comp_B?

It would be very helpful if someone has a time to explain this for all of us who do not understand this.

Thank you

PS. compA=debian, comp_B=gentoo

amitsharma_26 · 09-19-2006, 11:37 AM

Quote:

Originally Posted by sarajevo

iptables -t nat -A OUTPUT -s any/0 -d <x.x.x.x> -p tcp --dport 80 -j DNAT --to-destination 192.168.1.20:100
PS. compA=debian, comp_B=gentoo

That rule is absoultely fine.. nothing wrong with that.
Maybe at your gentoo box, some firewall would be blocking the incoming request at port #100. Check out.

I would suggest you to use any packet logger @ gentoo box to get into the base of this problem.

yongitz · 09-22-2006, 06:02 AM

why not try changing your --dport "port" to 100 too?! so your rule would now be iptables -t nat -A OUTPUT -s any/0 -d 80.65.170.142 -p tcp --dport 100 -j DNAT --to-destination 192.168.1.20:100