IP Tables Primer - Part 1
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This document discusses Linux firewalls and iptables. It provides an overview of firewall basics, packet basics, common Linux firewalls that use iptables, and some basic iptables commands. It then demonstrates examples of iptables rules to block ping requests, reject ping requests, and drop incoming web traffic on port 80 from a specific client IP address. The document is intended as an introduction to iptables and provides demonstrations of common rule types and formats.
IP Tables Primer - Part 1
- 1. IPTables Getting Started Nishanth Kumar n|u Bangalore chapter member n|u / OWASP / G4H / SecurityXploded meet 22 Feb 2014
- 2. Agenda • Firewall Basics • Packet Basics • Linux Firewalls • What you can do with IPTables • What you can’t do with IP Tables • What you need to know about IP Tables • Few Examples & Demo 22 Feb 2014
- 3. Firewalls Prevents Unauthorized access TO or FROM network. Hardware / Software / both 22 Feb 2014
- 4. What Firewalls do ? Filtering traffic based on POLICY Policy determines what is acceptable traffic Access control over traffic Accept or Deny May perform other duties Logging ( Forensics , SLA ) Flagging ( Intrusion Detection ) QOS ( bandwidth management , inbound &outbound traffic priority ) 22 Feb 2014
- 5. Typical Packet looks like … 22 Feb 2014
- 6. Linux Firewalls IP Cop Shore wall UFW – Uncomplicated Firewall Open BSD & PF Most of the above firewall intern uses IPTables . 22 Feb 2014
- 7. Some basic commands service iptables status The above command is used to check the status of iptables service iptables start The above command is used to start the iptables service iptables stop The above command is used to stop the iptables iptables –F or iptables --flush The above command is used to clean-up all the default rules and existing rules. 22 Feb 2014
- 8. Ping Block - DROP iptables -A INPUT -p icmp -j DROP 22 Feb 2014
- 9. Description of rule iptables -A INPUT -p icmp -j DROP Service PROTOCOL NAME APPEND INPUT Chain JUMP PROTOCOL TARGET 22 Feb 2014
- 10. Ping Block - REJECT iptables -A INPUT -p icmp -j REJECT 22 Feb 2014
- 11. Description of rule iptables -A INPUT -p icmp -j REJECT Service PROTOCOL NAME APPEND INPUT Chain JUMP PROTOCOL TARGET 22 Feb 2014
- 12. Web Server - Client Example iptables -A INPUT -i eth0 -p tcp --dport 80 -j DROP 22 Feb 2014
- 13. Description of rule iptables -A INPUT -i eth0 -p tcp --dport 80 -j DROP Service APPEND INPUT INTERFACE INPUT Chain PROTOCOL NAME Port Number PROTOCOL JUMP INTERFACE NAME Destination Port TARGET 22 Feb 2014
- 14. Web Server - Client Example - 1 192.168.99.12 192.168.99.11 iptables -A INPUT –s 192.168.99.12 -p tcp --dport 80 -j DROP 22 Feb 2014
- 15. Description of rule iptables -A INPUT -s 192.168.99.12 -p tcp --dport 80 -j DROP Service APPEND Source PROTOCOL NAME Port Number INPUT Chain PROTOCOL JUMP IP Address of the Source Destination Port TARGET 22 Feb 2014
- 16. Continue in Part 2 Thank you 22 Feb 2014