Network

IPs

Args of ip (before the action command)

-c: colored output
-j: json output
-j -p: json indented output
-d: display more information

Command `net-tools`	Command `iproute2`	Description
`ifconfig -a`	`ip addr`	Show IP address
`arp -a`	`ip neigh`	Show ARP table
`route`	`ip route`	Show network interfaces
`netstat -g`	`ip maddress`	multicast

# add ip
ip address add 10.0.0.1/24 dev eth0
# up
ip link set eth0 up

Utils file

# IPv4 addresses:
cat /proc/net/fib_trie

# hex-encoded port data:
cat /proc/net/tcp

# ARP
cat /proc/net/arp

Custom host resolution

You will need first need to ensure that the file /etc/nsswitch.conf is created

# /etc/nsswitch.conf

hosts:          files dns
networks:       files

Then you can create and use the file /etc/hosts to do a custom host resolution

# /etc/hosts
127.0.0.1       localhost
::1             localhost ip6-localhost ip6-loopback
192.168.1.45    my_server

Get network packets

# as root
tcpdump -i any

https://www.youtube.com/watch?v=hWc-ddF5g1I

Linux network namespaces

# root network namespace
ip link

ip netns add red
ip netns del green
ls /var/run/netns

ip netns list

ip netns exec red ip link

# do command under a namespace
ip netns exec red bash

Bridges

# need root
apt install bridge-utils

# create new interface NEW_INTERFACE
tunctl -u user -t NEW_INTERFACE
ifconfig NEW_INTERFACE up promisc


# create bridge BRIDGE
brctl addbr BRIDGE
ifconfig BRIDGE up promisc
brctl addif BRIDGE eth0
brctl addif BRIDGE NEW_INTERFACE

# show bridges
brctl show

ifconfig BRIDGE up

golb