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Documentation for the lecture:


1) General documentation on IPTABLES (CentOS and Ubuntu):

opt.pdf from the documentation folder (for now only in romanian)
from here, read at least the part of cautionary steps to do before configuring 
the firewall

2) About configuring firewall using UVW in Ubuntu:

https://www.digitalocean.com/community/tutorials/how-to-set-up-a-firewall-with-ufw-on-ubuntu-20-04

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Lab documentation as follows:

CentOS version:
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1) iptables configuration

https://www.cyberciti.biz/tips/linux-iptables-examples.html

Utilities for querying DNS servers (host, nslookup):
yum install bind-utils

1) Everything from 1-7, 9, 10
2) Only block incoming traffic (7.10)
3) block a certain website (family of adresses)  (11.1)

No longer requested for the test:
4) Drop Private Network Address On Public Interface (8)
5) Block or Allow ICMP Ping Request (15)
6) Drop or Accept Traffic From Mac Address (14)
7) Log and Drop Packets (12, 13)


Ubuntu:
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https://www.cyberciti.biz/faq/how-to-configure-firewall-with-ufw-on-ubuntu-20-04-lts/

1) Steps 1-6
2) Delete rules
3) Reset, reload, view logs
4) List the rules



Display various information:
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a) The lshw command displays various hardware information
		sudo lshw
without sudo you might get just a part of the information.

b) The lsusb command displays information about the USB ports and devices
		lsusb

c) The lslogin command displays information about known users in the system
		lslogin
	
d) 	The lscpu command displays information about the CPU architecture
		lscpu
		
e) Dispaly information about the open files
		lsof

f) The lsipc command shows information on the inter-process communication 
facilities
		lsipc
		
g) The lsblk command lists block devices, useful for finding out harddrive information
		lsblk
		
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The booting process for Ubuntu systems:
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    sudo ufw allow from 203.0.113.4 to any port 22