Iptable Linux Firewall

Firewall refers to a barrier that is used to limit the spread of fire. In the computing
world, it refers to a software or hardware-based network security system, which can be used
to control incoming and outgoing network traffic based on a set of rules. Out of the ten Linux
firewall, I suggest iptables. It is a user-space utility program that allows a system
administrator to configure the IP packet filter rules of the Linux kernel firewall, implemented
as different Netfilter modules. The filters are organized in different tables, which contain
chains of rules for how to treat network traffic packets. It is fast and first line of defense of a
Linux server protection. Some of its features that make it the best are listed below.
The INPUT, OUTPUT and FORWARD elements are chain-related in the Iptable
Linux firewall. This makes navigation simpler, efficient and safer. This also offers maximum
protection from malwares that can crush a computer system. Unlike other firewalls, iptables
makes use of the concept of separate rule tables for various kinds of packet processing
functionality (Hasan, 2020). These tables function independently which include filter table,
NAT and the specialized packet-handling mangle table. This feature eases organization of
documents especially excel spreadsheets. The filter table has two kinds of feature
extensions: target extensions and match extensions comprising REJECT, BALANCE AND
CLUSTERRIP.
The mangle table hand has two target extensions. The MARK module supports
assigning a value to the packet’s mark field that iptables maintains. The TOS module
supports setting the value of the TOS field in the IP header.  A NAT table device is a router
that is also changing the source and/or target ip-address in packets. In iptables it adds two
new chains.; PREROUTING allows altering of packets before they reach the INPUT chain
while POSTROUTING allows altering packets after they exit the OUTPUT chain. The

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NAT table has target extension modules for Source and Destination Address Translation and
for Port Translation. These modules support, MASQUERADE. This is a specialized form of
source NAT for connections that are assigned a temporary, changeable, dynamically assigned
IP address (such as a phone dial-up connection). It also supports REDIRECT, a specialized
form of destination NAT that redirects the packet to the local host, regardless of the address
in the IP header’s destination field.
Iptable firewall has the capability to check for stealth scans, which is not found in
other firewalls. For instance, TCP, transmission control protocol, is at will to choose the
largest segment size depending on the senders’ preference. Some of the upcoming feature of
iptables include experimental MIRROR target (Hasan, 2020). This enables retransition of a
packet after reversing the source and destination sections of the IP header.
In conclusion, after consideration of these salient features of Iptables Linux firewall, it
is evident why I suggest it over the others. It is suitable both for commercial and private use.
Any organization with bright visions should adopt it.

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Reference

Hasan, M. (2020, January 6). The 15+ Linux firewall software for protecting your Linux
system. UbuntuPIT.  https://www.ubuntupit.com/linux-firewall-software-for-
protecting-your-linux-systems/