System Security with IPTable Firewall

Running head: SYSTEM SECURITY WITH IPTABLE FIREWALL
System Security with IPTable Firewall
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Author Note

SYSTEM SECURITY WITH IPTABLE FIREWALL1
Executive Summary
A very important part of Linux system security is configuring of IPTables. Though IPTables
have a lot of functionalities they are mostly used by system administrators of business
organizations in blocking and allowing network traffic to and from their systems. The report
begins by presenting the solutions to the six requirements. These are rejecting all ssh
connections, allowing all ssh connections, denying ping between different clients systems,
rejecting all traffic to and from port 80, blocking all inbound traffic to a the IP of a specific
interface and allowing all traffic to and from port 80. After this exercise the report discusses
the advantages and disadvantages of firewalls and iptables. Then the report explains the
significance of circuit relay firewall to secure communications through SOCKS packages.
After that the report ends with concluding notes.

SYSTEM SECURITY WITH IPTABLE FIREWALL2
Table of Contents
Introduction................................................................................................................................3
Solution......................................................................................................................................3
1. Reject all ssh packets.........................................................................................................3
2. Allow ssh remote connections...........................................................................................4
3. Deny ping...........................................................................................................................6
Before the rules are applied................................................................................................7
After rules are applied........................................................................................................7
4. Reject all traffic coming to port 80....................................................................................8
5. Block incoming traffic connection to your IP address of your virtual machine................9
IPTable firewall rule to block inbound traffic....................................................................9
Demonstration from Windows.........................................................................................10
6. Allow traffic coming to port 80 (inbound) but reject traffic going out (outbound) through
port 80..................................................................................................................................11
A...........................................................................................................................................13
Firewall with iptable........................................................................................................13
B...........................................................................................................................................15
Discuss the role and significance of circuit relay firewall in securing communication by
reflecting on the SOCKS package specified in RFC1928...............................................15
Conclusion................................................................................................................................15
Bibliography.............................................................................................................................17

SYSTEM SECURITY WITH IPTABLE FIREWALL3
Introduction
The following report attempts to highlight the use of IPTable firewall and how
relevant it is among Linux users today. The report also goes on to discuss the drawbacks of
this firewall while mentioning about the circuit relay firewall as well. This report starts by
answering the six requirements of allowing connections and denying connections as well as
enabling and disabling different types of ports. These are rejecting all ssh connections,
allowing all ssh connections, denying ping between different clients systems, rejecting all
traffic to and from port 80, blocking all inbound traffic to a the IP of a specific interface and
allowing all traffic to and from port 80. After this exercise the report discusses the benefits
and drawbacks of firewalls and iptables. Then the report explains the significance of circuit
relay firewall to secure communications through those SOCKS packages which are specified
by RFC1928. After that the report ends with concluding notes.
Solution
1. Reject all ssh packets.
Firewall rules for blocking all SSH connections. The Kali Linux terminal commands
that have been used to configure the rules are as provided below:
iptables –A INPUT –p tcp --dport 22 –j DROP
iptables –A INPUT –p tcp --sport 22 –j DROP
iptables –A OUTPUT –p tcp --dport 22 –j DROP
iptables –A INPUT –p tcp --sport 22 –j DROP