Linux/iptables

Tables Chains FILTER INPUT OUTPUT FORWARD NAT PREROUTING OUTPUT POSTROUTING MANGLE (modify ip headers) PREROUTING POSTROUTING OUTPUT INPUT FORWARD RAW (connection tracking) PREROUTING OUTPUT SECURITY		Targets REJECT DROP ACCEPT RETURN MASQUERADE

Basics

iptables
         -A (append - add rule at end)             -i (input interface)          -j (target)
         -C (check)                                -o (output interface)
         -D (delete - remove rule)                 -s (source address)    
         -F (flush - remove all rules)             -d (destination address)
         -I (insert - add at position)              
         -L (list - show all rules in chain)       -p      (protocol (tcp/udp))
         -N (new chain)                            --dport (port)
         -X (delete chain)

         -t (table to manipulate (default: filter)

         -n (numeric output of addresses and ports)

View state

iptables -L

raspi wifi to ethernet

• rc.local
  • iptables --table nat --append POSTROUTING --out-interface wlan0 -j MASQUERADE
  • iptables --append FORWARD --in-interface eth0 -j ACCEPT