*nat
:PREROUTING ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
-A POSTROUTING -s {{ vpn_network_ipv6 }} -m policy --pol none --dir out -j MASQUERADE
COMMIT
*filter
:INPUT DROP [0:0]
:FORWARD DROP [0:0]
:OUTPUT ACCEPT [0:0]
:ICMPV6-CHECK - [0:0]
:ICMPV6-CHECK-LOG - [0:0]
-A INPUT -i lo -j ACCEPT
-A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A INPUT -p esp -j ACCEPT
-A INPUT -m ah -j ACCEPT
# rate limit ICMP traffic per source
-A INPUT -p icmpv6 --icmpv6-type echo-request -m hashlimit --hashlimit-upto 5/s --hashlimit-mode srcip --hashlimit-srcmask 32 --hashlimit-name icmp-echo-drop -j DROP
-A INPUT -p udp -m multiport --dports 500,4500 -j ACCEPT
-A INPUT -p tcp --dport 22 -m conntrack --ctstate NEW -j ACCEPT
# TODO:
# The IP of the resolver should be bound to a DUMMY interface.
# DUMMY interfaces are the proper way to install IPs without assigning them any
# particular virtual (tun,tap,...) or physical (ethernet) interface.
-A INPUT -d fcaa::1 -p udp --dport 53 -j ACCEPT
-A FORWARD -j ICMPV6-CHECK
-A FORWARD -p tcp --dport 445 -j DROP
-A FORWARD -p udp -m multiport --ports 137,138 -j DROP
-A FORWARD -p tcp -m multiport --ports 137,139 -j DROP
-A FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A FORWARD -m conntrack --ctstate NEW -s {{ vpn_network_ipv6 }} -m policy --pol ipsec --dir in -j ACCEPT
# this is so potential malicious traffic can not reach anywhere over the server
# https://www.insinuator.net/2016/05/cve-2016-1409-ipv6-ndp-dos-vulnerability-in-cisco-software/
# other software implementations might be at least as broken as the one in CISCO gear.
-A ICMPV6-CHECK -p icmpv6 -m hl ! --hl-eq 255 --icmpv6-type router-solicitation -j ICMPV6-CHECK-LOG
-A ICMPV6-CHECK -p icmpv6 -m hl ! --hl-eq 255 --icmpv6-type router-advertisement -j ICMPV6-CHECK-LOG
-A ICMPV6-CHECK -p icmpv6 -m hl ! --hl-eq 255 --icmpv6-type neighbor-solicitation -j ICMPV6-CHECK-LOG
-A ICMPV6-CHECK -p icmpv6 -m hl ! --hl-eq 255 --icmpv6-type neighbor-advertisement -j ICMPV6-CHECK-LOG
-A ICMPV6-CHECK-LOG -j LOG --log-prefix "ICMPV6-CHECK-LOG DROP "
-A ICMPV6-CHECK-LOG -j DROP
COMMIT