*filter

#  Allow all loopback (lo0) traffic and drop all traffic to 127/8 that doesn't use lo0
-A INPUT -i lo -j ACCEPT
-A INPUT -d 127.0.0.0/8 -j REJECT

#  Accept all established inbound connections
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

#  Block anything from China
#  These rules are pulled from ipset's china list
#  The source file is at /etc/cn.zone (which in turn is generated by a shell script at /etc/block-china.sh )
-A INPUT -p tcp -m set --match-set china src -j DROP

#  Block bittorent
-A INPUT -p tcp --dport 80 -m string --algo bm --string "Bittorrent" --to 1000 -j DROP
-A INPUT -p tcp --dport 80 -m string --algo bm --string "GET /announce" --to 1000 -j DROP

#  Limit connection speed to avoid DDOS
-A INPUT -p tcp --dport 80 -m state --state NEW -m limit --limit 50/minute --limit-burst 200 -j ACCEPT

#  Allow all outbound traffic - you can modify this to only allow certain traffic
-A OUTPUT -j ACCEPT

#  Allow HTTP and HTTPS connections from anywhere (the normal ports for websites and SSL).
-A INPUT -p tcp --dport 80 -j ACCEPT
-A INPUT -p tcp --dport 443 -j ACCEPT

#  Allow SSH connections
#
#  The -dport number should be the same port number you set in sshd_config
#
-A INPUT -p tcp -m state --state NEW --dport 2222 -j ACCEPT

#  Allow ping
-A INPUT -p icmp -j ACCEPT

#  Log iptables denied calls
-A INPUT -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7

#  Drop all other inbound - default deny unless explicitly allowed policy
-A INPUT -j DROP
-A FORWARD -j DROP

COMMIT

110.255.172.42 - - [26/Apr/2015:18:05:41 +1200] "GET /announce.php?info_hash=M%3A%89%E1%86%9D%60%A7I%23%D6%99r%04%D7t%06%5F%A6%CC&peer_id=%2DSD0100%2D%E9%B1%EF%11A%CC%FB%94%EDl%23%8A&ip=101.28.113.60&port=8644&uploaded=1503508047&downloaded=1503508047&left=0&numwant=200&key=9253&compact=1 HTTP/1.0" 410 225 "-" "Bittorrent"

Chain INPUT (policy ACCEPT)
target     prot opt source               destination
ACCEPT     all  --  anywhere             anywhere
REJECT     all  --  anywhere             127.0.0.0/8          reject-with icmp-port-unreachable
ACCEPT     all  --  anywhere             anywhere             state RELATED,ESTABLISHED
DROP       tcp  --  anywhere             anywhere             match-set china src
DROP       tcp  --  anywhere             anywhere             tcp dpt:http STRING match  "Bittorrent" ALGO name bm TO 1000
DROP       tcp  --  anywhere             anywhere             tcp dpt:http STRING match  "GET /announce" ALGO name bm TO 1000
ACCEPT     tcp  --  anywhere             anywhere             tcp dpt:http state NEW limit: avg 50/min burst 200
ACCEPT     tcp  --  anywhere             anywhere             tcp dpt:http
ACCEPT     tcp  --  anywhere             anywhere             tcp dpt:https
ACCEPT     tcp  --  anywhere             anywhere             state NEW tcp dpt:2222
ACCEPT     icmp --  anywhere             anywhere
LOG        all  --  anywhere             anywhere             limit: avg 5/min burst 5 LOG level debug prefix "iptables denied: "
DROP       all  --  anywhere             anywhere

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination
DROP       all  --  anywhere             anywhere

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination
ACCEPT     all  --  anywhere             anywhere