Hmm. I don't think bridging copies the packets MAC address over. it just copies the packet data with it's source and destination IPs. Can I ask what the mac address is used for, or needed for? Is it for some authenticity reasons? -----Original Message----- From: Michael Stilmant [mailto:ml-netfilter@xxxxxxxxx] Sent: Saturday, May 24, 2003 1:07 AM To: netfilter@xxxxxxxxxxxxxxxxxxx Subject: transparent tcp proxy Hello, First of all, an hello from a new user on this mailing list. and finally my actual problem. I'm need to make a transparent proxy for an billing application. To to that I need to put myself in the middle point of a protocol exchange not thinked to be easy done with a proxy. So to do that I've done this installation: I've have a computer where I place transparent proxy via ebtables this is B. (no special rules : just ones to activate a transparent proxy: brctl addbr mybridge brctl addif mybridge eth0 brctl addif mybridge eth1 ifconfig eth0 0.0.0.0 ifconfig eth1 0.0.0.0 ifconfig mybridge up ifconfig mybridge 10.0.0.225 route add default gw 10.0.0.254 ) A and C communicate with all normal exchange 10.0.0.225 +--------+ | B | +-----+ | | +-----+ | A +-----------[ebtables]----------| C | +-----+ +--------+ +-----+ 10.0.0.3 10.0.0.32 I've place this Iptables rules iptables -t nat -A PREROUTING -i eth1 -d 10.0.0.3 -p tcp --dport 3435 -j DNAT --to-destination 10.0.0.225:3625 iptables -t nat -A POSTROUTING -o eth0 -d 10.0.0.3 -p tcp --dport 3435 -j SNAT --to-source 10.0.0.32 so with that when C want to connect the A:3435 service all traffic is oriented to B and when B send traffic to A: A see C ip address. -> full transparent. But there are a big problem: Address Mac used from B to A is not the MAC address. Not a problem since i don't want really be transparent but other traffic form C go to A directly with the good MAC and traffic from B to A have an other MAC. so switch or other router in the A side see 10.0.0.32 sometime with C Mac and other time with B MAC .. gloupspss ?? .. :-D I need to find a way to read mac address from a connection from C and set this MAC when I start a connection to A from B have you some clues ? (allready send the same question on the ebtables ailin list .. perhaps with a function from there there are a solution ... ) thanks Michael Stilmant
