Masquerading 101

• The following turns on masquerading for ppp0 and blocks incoming connections on ppp0.

  • iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE
  • iptables -A INPUT -i ppp0 -m state --state NEW,INVALID -j DROP
  • iptables -A FORWARD -i ppp0 -m state --state NEW,INVALID -j DROP
  • sysctl -w net.ipv4.conf.all.rp_filter=1
  • sysctl -w net.ipv4.ip_forward=1

Notes: