root@OpenWrt:~# iptables -L Chain INPUT (policy DROP) target prot opt source destination DROP all -- anywhere anywhere state INVALID ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED DROP tcp -- anywhere anywhere tcp option=!2 flags:SYN/SYN input_rule all -- anywhere anywhere ACCEPT all -- anywhere anywhere ACCEPT icmp -- anywhere anywhere ACCEPT gre -- anywhere anywhere REJECT tcp -- anywhere anywhere reject-with tcp-reset REJECT all -- anywhere anywhere reject-with icmp-port-unreachable Chain FORWARD (policy DROP) target prot opt source destination DROP all -- anywhere anywhere state INVALID TCPMSS tcp -- anywhere anywhere tcp flags:SYN,RST/SYN TCPMSS clamp to PMTU ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED forwarding_rule all -- anywhere anywhere ACCEPT all -- anywhere anywhere ACCEPT all -- anywhere anywhere Chain OUTPUT (policy DROP) target prot opt source destination DROP all -- anywhere anywhere state INVALID ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED output_rule all -- anywhere anywhere ACCEPT all -- anywhere anywhere REJECT tcp -- anywhere anywhere reject-with tcp-reset REJECT all -- anywhere anywhere reject-with icmp-port-unreachable Chain forward_vlan1 (1 references) target prot opt source destination Chain forwarding_rule (1 references) target prot opt source destination forward_vlan1 all -- anywhere anywhere Chain input_rule (1 references) target prot opt source destination input_vlan1 all -- anywhere anywhere Chain input_vlan1 (1 references) target prot opt source destination Chain output_rule (1 references) target prot opt source destination