it-engineer-pro

#!/bin/bash
# wget -nv -O named.root https://www.internic.net/domain/named.root
echo "[i] Backing up root.hints ..."
cd /var/lib/unbound
sudo cp root.hints $(date +%F).root.hints

if [ -s $(date +%F).root.hints ]
then
     echo "[✓] Backup root.hints success!"
     echo ""

it-engineer-pro

BIND - delegate a sub domain for a zone

The scenario:

• DNS zone myzone.com defined in BIND.
• Authoritative name server at 123.16.123.1.
• Subzone sub.myzone.com with an authoritative name server at 123.16.123.10.
• Wishing to forward sub-zone to authoritative name server.

Config

it-engineer-pro

IP Tables (iptables) Cheat Sheet

IPTables is the Firewall service that is available in a lot of different Linux Distributions. While modifiying it might seem daunting at first, this Cheat Sheet should be able to show you just how easy it is to use and how quickly you can be on your way mucking around with your firewall.

Resources

The following list is a great set of documentation for iptables. I used them to compile this documentation.

• How-To Geek: The Beginner’s Guide to iptables, the Linux Firewall: https://www.howtogeek.com/177621/the-beginners-guide-to-iptables-the-linux-firewall/
• IPTables Essentials: Common Firewall Rules and COmmands https://www.digitalocean.com/community/tutorials/iptables-essentials-common-firewall-rules-and-commands

it-engineer-pro

#!/bin/bash

echo -n "loading ipv4 packet filter... "

### clear tables
iptables --flush
iptables --delete-chain
iptables --table mangle --flush
iptables --table mangle --delete-chain

it-engineer-pro

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