Listing 1. TPROXY Rules

iptables -t tproxy -P PREROUTING ACCEPT
iptables -t tproxy -A PREROUTING -i eth1 -j PRblue
iptables -t tproxy -A PREROUTING -i eth2 -j PRpurple
iptables -t tproxy -A PREROUTING -i eth0 -j PRred

iptables -t tproxy -P OUTPUT ACCEPT

iptables -t tproxy -N PRblue
iptables -t tproxy -A PRblue -p tcp --dport 80 \
  -j TPROXY --on-port 50080
iptables -t tproxy -A PRblue -p tcp --dport 22 \
  ! -d firewall.example.net -j TPROXY --on-port 50022

iptables -t tproxy -N PRpurple

iptables -t tproxy -N PRred
iptables -t tproxy -A PRred -p tcp --dport 80 \
  -j TPROXY --on-port 50080