https://www.theurbanpenguin.com/rp_filter-and-lpic-3-linux-security/

https://help.ubuntu.com/community/IptablesHowTo

  [[ NEWFW ]]

  * 
  * [root@syslog ~]# vi /etc/sysconfig/iptables
  * # Generated by iptables-save v1.4.7 on Wed Jul 20 17:58:53 2016
  * *mangle
  * :PREROUTING ACCEPT [1153:130274]
  * :INPUT ACCEPT [1150:130064]
  * :FORWARD ACCEPT [0:0]
  * :OUTPUT ACCEPT [25:2721]
  * :POSTROUTING ACCEPT [25:2721]
  * -A PREROUTING -p tcp -m tcp --dport 135:139 -j DROP
  * -A PREROUTING -p udp -m udp --dport 135:139 -j DROP
  * -A PREROUTING -p tcp -m tcp --dport 445 -j DROP
  * -A PREROUTING -p udp -m udp --dport 445 -j DROP
  * -A PREROUTING -p udp -m multiport --ports 445,1433,1434,2002,4156,1978,27444,10100,1812,10064,389,6346 -j DROP
  * -A PREROUTING -p tcp -m multiport --ports 445,1433,1434,2002,4156,1978,27444,10100,1812,10064,389,6346 -j DROP
  * -A PREROUTING -p tcp -m tcp --dport 25 -j DROP
  * -A PREROUTING -p tcp -m tcp --dport 110 -j DROP
  * -A PREROUTING -p tcp -m tcp --dport 143 -j DROP
  * -A PREROUTING -p tcp -m tcp --dport 80 -j DROP
  * -A PREROUTING -p tcp -m tcp --dport 8080 -j DROP
  * -A PREROUTING -p tcp -m tcp --dport 123 -j DROP
  * -A PREROUTING -p tcp -m tcp --dport 53 -j DROP
  * -A PREROUTING -p udp -m udp --dport 53 -j DROP
  * "/etc/sysconfig/iptables" 49L, 2257C
  * # Generated by iptables-save v1.4.7 on Wed Jul 20 17:58:53 2016
  * *mangle
  * :PREROUTING ACCEPT [1153:130274]
  * :INPUT ACCEPT [1150:130064]
  * :FORWARD ACCEPT [0:0]
  * :OUTPUT ACCEPT [25:2721]
  * :POSTROUTING ACCEPT [25:2721]
  * -A PREROUTING -p tcp -m tcp --dport 135:139 -j DROP
  * -A PREROUTING -p udp -m udp --dport 135:139 -j DROP
  * -A PREROUTING -p tcp -m tcp --dport 445 -j DROP
  * # Generated by iptables-save v1.4.7 on Wed Jul 20 17:58:53 2016
  * *mangle
  * :PREROUTING ACCEPT [1153:130274]
  * :INPUT ACCEPT [1150:130064]
  * :FORWARD ACCEPT [0:0]
  * :OUTPUT ACCEPT [25:2721]
  * :POSTROUTING ACCEPT [25:2721]
  * -A PREROUTING -p tcp -m tcp --dport 135:139 -j DROP
  * -A PREROUTING -p udp -m udp --dport 135:139 -j DROP
  * -A PREROUTING -p tcp -m tcp --dport 445 -j DROP
  * -A PREROUTING -p udp -m udp --dport 445 -j DROP
  * -A PREROUTING -p udp -m multiport --ports 445,1433,1434,2002,4156,1978,27444,10100,1812,10064,389,6346 -j DROP
  * -A PREROUTING -p tcp -m multiport --ports 445,1433,1434,2002,4156,1978,27444,10100,1812,10064,389,6346 -j DROP
  * -A PREROUTING -p tcp -m tcp --dport 25 -j DROP
  * -A PREROUTING -p tcp -m tcp --dport 110 -j DROP
  * -A PREROUTING -p tcp -m tcp --dport 143 -j DROP
  * -A PREROUTING -p tcp -m tcp --dport 80 -j DROP
  * -A PREROUTING -p tcp -m tcp --dport 8080 -j DROP
  * -A PREROUTING -p tcp -m tcp --dport 123 -j DROP
  * -A PREROUTING -p tcp -m tcp --dport 53 -j DROP
  * -A PREROUTING -p udp -m udp --dport 53 -j DROP
  * -A PREROUTING -p udp -m udp --dport 123 -j DROP
  * COMMIT
  * # Completed on Wed Jul 20 17:58:53 2016
  * # Generated by iptables-save v1.4.7 on Wed Jul 20 17:58:53 2016
  * *filter
  * :INPUT ACCEPT [0:0]
  * :FORWARD ACCEPT [0:0]
  * :OUTPUT ACCEPT [1047:203052]
  * :syn_flood - [0:0]
  * -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
  * -A INPUT -p icmp -j ACCEPT
  * -A INPUT -i lo -j ACCEPT
  * -A INPUT -p tcp -m state --state NEW -m tcp --dport 2222 -j ACCEPT
  * -A INPUT -p tcp -m state --state NEW -m tcp --dport 80 -j ACCEPT
  * -A INPUT -p tcp -m state --state NEW -m tcp --dport 8000 -j ACCEPT
  * -A INPUT -p udp -m state --state NEW -m udp --dport 514 -j ACCEPT
  * -A INPUT -p tcp -m state --state NEW -m tcp --dport 514 -j ACCEPT
  * -A INPUT -j REJECT --reject-with icmp-host-prohibited
  * -A INPUT -p icmp -m limit --limit 1/sec --limit-burst 1 -j ACCEPT
  * -A INPUT -p icmp -m limit --limit 1/sec --limit-burst 1 -j LOG --log-prefix "PING-DROP:"
  * -A INPUT -p icmp -j DROP
  * -A INPUT -p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -j syn_flood
  * -A FORWARD -j REJECT --reject-with icmp-host-prohibited
  * -A OUTPUT -p icmp -j ACCEPT
  * -A syn_flood -m limit --limit 1/sec --limit-burst 3 -j RETURN
  * -A syn_flood -j DROP
  * COMMIT
  * # Completed on Wed Jul 20 17:58:53 2016
  *