Networking on Terminal

Wireguard VPN networking

Mon, 09 Nov 2026 00:00:00 +0000

Background

As easier or ad-hoc VPN solution to openvpn, wireguard provides user space tools for point-to-point networking with roaming clients.

One static public host is needed.

Network topology

Server

Any publicly reachable host with optional DNS name.

It also has private address 172.16.0.1 for WG interface.

Roaming peer 1

Using any network anywhere. WG address is 172.16.0.2

Package setup for all hosts

sudo apt install wireguard-tools

Key generation

Server

wg genkey >/root/wg/srv.key
wg pubkey </root/wg/srv.key >/root/wg/srv.pub

Peer 1

wg genkey >/root/wg/stinky.key
wg pubkey </root/wg/stinky.key >/root/wg/stinky.pub

Server setup

Allow traffic at udp/12345

ufw allow udp/12345 comment 'wireguard'

Public server config

The peer key below is stinky.pub contents

Test ethernet cables with two local interfaces

Thu, 29 May 2025 00:00:00 +0000

Connect (usb) ethernet adapters and some cable between them
Disable both interfaces from network settings / network manager

Check interface visibility

# ip a | grep enx
enx7cc2c6448e83: <BROADCAST,MULTICAST,UP,LOWER_UP>
enx60a4b7ddea36: <BROADCAST,MULTICAST,UP,LOWER_UP>

Setup first interface

# add IP address to 1st interface
ip a add 10.10.10.10/24 dev enx7cc2c6448e83

Setup new network namespace and second interface

# create new network namespace
ip netns add lan2

# move 2nd interface to new namespace
ip link set enx60a4b7ddea36 netns lan2

# bring up 2nd interface
ip netns exec lan2 ip link set dev enx60a4b7ddea36 up

# add IP address to 2nd interface
ip netns exec lan2 ip a add 10.10.10.11/24 dev enx60a4b7ddea36

Test connection between interfaces

# ping 10.10.10.11

PING 10.10.10.11 (10.10.10.11) 56(84) bytes of data.
64 bytes from 10.10.10.11: icmp_seq=1 ttl=64 time=0.755 ms
64 bytes from 10.10.10.11: icmp_seq=2 ttl=64 time=0.743 ms
64 bytes from 10.10.10.11: icmp_seq=3 ttl=64 time=1.03 ms

3 packets transmitted, 3 received, 0% packet loss, time 2087ms

OpenVPN networking

Thu, 03 Apr 2025 00:00:00 +0000

Package setup for building files at any host computer

sudo apt install easy-rsa openssl openvpn

Package setup for OpenVPN server

sudo apt install openvpn

Create directory for building and keeping keyfiles

mkdir ~/vpn_repo
cd ~/vpn_repo

* From here on, everything happens at ~/vpn_repo !!! *

Fetch & prepare easy-tls

wget https://raw.githubusercontent.com/TinCanTech/easy-tls/refs/heads/master/easytls
chmod 750 easytls

For creating all the needed OpenVPN server files

cat >server.sh

#!/bin/bash

# cert & ca expiry 10 years
export EASYRSA_KEY_SIZE=2048
export EASYRSA_CA_EXPIRE=3650
export EASYRSA_CERT_EXPIRE=3650

TARGET=$1
USER=$2
PASS=$3

if [ -z $TARGET ]
then
 echo "Give servername as arg"
 exit
fi

make-cadir $TARGET
if [ $? -eq 0 ]
 then
 cd $TARGET

 # build server cert package
 ./easyrsa init-pki
 echo $TARGET | ./easyrsa build-ca nopass
 ./easyrsa gen-dh
 echo yes | ./easyrsa build-server-full $TARGET nopass

 # prepare tls-auth key
 if [[ ! -d pki/easytls ]]
 then
 ../easytls init-tls
 ../easytls build-tls-auth
 fi

 cd ..
 mkdir -p out
 # symlink all files needed on server side
 ln -srf $TARGET/pki/private/$TARGET.key out/
 ln -srf $TARGET/pki/ca.crt out/${TARGET}_ca.crt
 ln -srf $TARGET/pki/easytls/tls-auth.key out/${TARGET}_tls-auth.key
 ln -srf $TARGET/pki/dh.pem out/${TARGET}_dh.pem
 ln -srf $TARGET/pki/issued/$TARGET.crt out/

 echo "#### OpenVPN server files"
 find out | tail +2
 echo "####"
 echo "Copy these files to server /etc/openvpn/server/"
fi

For creating client profiles

cat >gen_user.sh

Thunderbolt networking

Mon, 24 Mar 2025 00:00:00 +0000

Setup

Connect USB4/TB cable between computers. Stay vigilant, most cables are not USB4/TB capable.

Host A:

modprobe thunderbolt-net
ip a add 10.10.10.10/24 dev thunderbolt0

Host B:

ip a add 10.10.10.11/24 dev thunderbolt0

Test network

# Host A:
iperf -s

# Host B:
iperf -i 10 -c 10.10.10.10

Results

------------------------------------------------------------
Client connecting to 10.10.10.10, TCP port 5001
TCP window size: 16.0 KByte (default)
------------------------------------------------------------
[ 1] local 10.10.10.11 port 53846 connected with 10.10.10.10
[ ID] Interval Transfer Bandwidth
[ 1] 0.0000-10.0000 sec 21.8 GBytes 18.7 Gbits/sec
[ 1] 0.0000-10.0019 sec 21.8 GBytes 18.7 Gbits/sec

Usage

Use the interfaces as any other network over ssh, rsync, netcat, scp etc

Networking on Terminal

Wireguard VPN networking

Background

Network topology

Server

Roaming peer 1

Package setup for all hosts

Key generation

Server

Peer 1

Server setup

Allow traffic at udp/12345

Public server config

Test ethernet cables with two local interfaces

OpenVPN networking

Package setup for building files at any host computer

Package setup for OpenVPN server

Create directory for building and keeping keyfiles

*** From here on, everything happens at ~/vpn_repo !!! ***

Fetch & prepare easy-tls

For creating all the needed OpenVPN server files

For creating client profiles

Thunderbolt networking

Setup

Test network

Results

Usage

* From here on, everything happens at ~/vpn_repo !!! *