Please explaing IP redirection for proxy!

salvor_hardin · 06-27-2009, 01:55 AM

I was wondering should I post this in networking section or Linux, since this is for Linux system I decided to post it here...

It is about Squid3 proxy. I configured all except one last step. I need transparent proxy, I have found lots of stuff but can't figure it out. Look at the next lines:

Last but not the least we need to redirect the HTTP traffic to your new shiny proxy

iptables -t nat -A PREROUTING -i eth1 -p tcp -m tcp --dport 80 -j DNAT --to-destination 192.168.0.1:3128
iptables -t nat -A PREROUTING -i eth0 -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 3128

where eth1, eth0 are the LAN, WAN devices and 192.168.0.1 is the IP address of your LAN device.

I assume that this is configuration when using 2 NIC-s on one computer. (eth0, eth1). I have one NIC on PC and NAT gateway connected to my PC. On NAT i just configure external proxy to point out to my machine! So I have eth0 which would be my LAN device that is connected to NAT. But there is no eth1 interface! anybody has any idea how should i preroute this??

06-27-2009, 01:55 AM	#1 (permalink)
salvor_hardin Registered User Join Date: May 2009 Location: Zadar, Croatia Posts: 20 OS: XP, Ubuntu	Please explaing IP redirection for proxy! I was wondering should I post this in networking section or Linux, since this is for Linux system I decided to post it here... It is about Squid3 proxy. I configured all except one last step. I need transparent proxy, I have found lots of stuff but can't figure it out. Look at the next lines: Last but not the least we need to redirect the HTTP traffic to your new shiny proxy iptables -t nat -A PREROUTING -i eth1 -p tcp -m tcp --dport 80 -j DNAT --to-destination 192.168.0.1:3128 iptables -t nat -A PREROUTING -i eth0 -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 3128 where eth1, eth0 are the LAN, WAN devices and 192.168.0.1 is the IP address of your LAN device. I assume that this is configuration when using 2 NIC-s on one computer. (eth0, eth1). I have one NIC on PC and NAT gateway connected to my PC. On NAT i just configure external proxy to point out to my machine! So I have eth0 which would be my LAN device that is connected to NAT. But there is no eth1 interface! anybody has any idea how should i preroute this??