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

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

#!/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 ""

flaviovs

Iptables(8) TARPIT is a useful security mechanism that can slow down or stop attacks on a network. If everyone used TARPIT to block attackers, in theory their resources would be exhausted as their connection attempts would be delayed, which would discouraged people from attempting unauthorized access. Here's a brief description of how TARPIT works:

To achieve this tar pit state, iptables accepts the incoming TCP/IP connection and then switches to a zero-byte window. This forces the attacker's system to stop sending data, rather like the effect of pressing Ctrl-S on a terminal. Any attempts by the attacker to close the connection are ignored, so the connection remains active and typically times out after only 12–24 minutes. This consumes resources on the attacker's system but not

lyjacky11

#!/bin/bash

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 ""

egernst

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

davydany

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

magnetikonline

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