On Thu, 2008-10-30 at 01:24 +0530, Arun Srinivasan wrote:
Thank you.
Currently am facing an issue.. dunno if it is an issue. please clarify.
In a Linux box with tproxy4 (tproxy4-2.6.26-200809262032), I have two proxies, proxy-1 listening on port x and proxy-2 on port y.
With the tproxy rules (tproxy-mark, -m socket, and policy routing), I could redirect the incoming traffic to proxy-1 that listens on port x. However, the request from proxy-1 could not be redirected to proxy-2.
The second redirection from proxy-1 from proxy-2 is attempted through NAT - OUTPUT rule.
The configured rules are given below: ++++++++++++ FOR PROXY-1 +++++++++++++++ iptables -t mangle -A PREROUTING -p tcp --dport 80 -j TPROXY --on-port <proxy-1 port> --tproxy-mark 0x1/0x1 ip rule add fwmark 0x1 lookup 100 ip route add local 0.0.0.0/0 dev lo table 100
iptables -t mangle -N DIVERT iptables -t mangle -I PREROUTING -p tcp -m socket -j DIVERT iptables -t mangle -A DIVERT -j MARK --set-mark 0x1 iptables -t mangle -A DIVERT -j ACCEPT +++++++++++++++++++++++++++++++++++++++++++++++
+++++++++++ FOR PROXY-2 +++++++++++++++++++++++++++++++++++++ iptables -t nat -A OUTPUT -p tcp --dport 80 -j DNAT --to <Interface IP>:<proxy-2 port> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
The rule for proxy-2 makes only the TCP-SYN packet from proxy-1 to be redirected. Three-way handshake is not successful.
Am I missing out anything or is this the intended behavior?
This DNAT is a different matter, it has no connection to tproxy. Please check where the SYN-ACK is going (via tcpdump), it should be properly NAT-ed both ways. Please check the conntrack table whether the appriopriate NAT mapping is there. -- Bazsi