kandulaganesh

Some examples of SNAT, DNAT with iptables with comments

mainly used in start-up script

How to test 'safely'

When we play with iptables aka firewall we might end up in situation, where we execute rule, which has unforseen impact - lock yourself out. Recovering from this situation is necessity.

How to:

Enable reboot via SMS.

Test all commands in shell first before putting them into Start-up script. This way the command will be wiped out, when unit is rebooted.

masquarade all outgoing packets to be WLAN0 IP

Tcpdump

Tcpdump is a commandline tool that is used to dump traffic on a network. This tool comes in hand when you want to analyse network captures within the command line. Basically it can do most of the wireshark job.

NOTE This guide might not be complete it just serve as a reference to me.

Additional Note & Reference

The netfilter hooks in the kernel and where they hook in the packet flow

The figure below calls out

The netfilter hooks
The order of table traversal

	# Modify this file accordingly for your specific requirement.
	# http://www.thegeekstuff.com
	# 1. Delete all existing rules
	iptables -F

	# 2. Set default chain policies
	iptables -P INPUT DROP
	iptables -P FORWARD DROP
	iptables -P OUTPUT DROP

	import requests
	from playsound import playsound
	import sys
	import time
	import pytz
	from datetime import datetime

	subscribed_centers=["Bus Depo Buharanpuram Khammam","Rica Bazar High School KMM","Musthafanagar UPHC"]
	search_dates=["31-05-2021","01-06-2021","02-06-2021"]