*filter
:INPUT DROP [0:0]
:FORWARD DROP [0:0]
:OUTPUT ACCEPT [0:0] 

# allow established connections
-A INPUT   -m state --state RELATED,ESTABLISHED -j ACCEPT
-A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT

# allow traffic from private LAN
-A INPUT   -i eth1 -j ACCEPT
-A FORWARD -i eth1 -j ACCEPT

# allow icmp
-A INPUT -p icmp -j ACCEPT

# allow loopback
-A INPUT -i lo -j ACCEPT

# uni subnets
:uni - [0:0]
-A INPUT -s 141.30.0.0/16 -j uni
-A INPUT -s 141.76.0.0/16 -j uni

# reject unknown traffic with nice errors
-A INPUT -p tcp -j REJECT --reject-with tcp-reset
-A INPUT -p udp -j REJECT --reject-with icmp-port-unreachable
-A INPUT -j REJECT --reject-with icmp-proto-unreachable

# ---------------------------------------------------------------
# internal traffic
#

:internal - [0:0]
-A uni -j internal
-A internal -p tcp --dport 22 -j ACCEPT
-A internal -p tcp --dport 80 -j ACCEPT
-A internal -p tcp --dport 443 -j ACCEPT

# ---------------------------------------------------------------
# public traffic  

:public - [0:0]
-A INPUT -j public

# ---------------------------------------------------------------

COMMIT

*nat
:PREROUTING ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
:OUTPUT ACCEPT [0:0] 

# masquerading
-A POSTROUTING -o eth0 -j MASQUERADE

COMMIT