Round-robin load-balancing between two VPNs with iptables and policy-based routing

Sun, 09 Jun 2024 11:52:37 +0000

Experiment 1

We want to send http traffik generated by our computer through a VPN tunnel.

VPN tunnels

Create two VPN tunnels:

openvpn --config au.ovpn
openvpn --config at.ovpn

Two new interfaces will be created: tun0 and tun1.

Two configs should prevent setting of default gateways:

pull-filter ignore redirect-gateway

Routing

Create a new routing table:

echo "201 vpn1" >> /etc/iproute2/rt_tables

and add default routing to the table:

ip route add default dev tun1 table vpn1

Check:

Network based message collector with socat

Thu, 30 May 2024 11:52:37 +0000

Overview

The simplest message collector code can be implemented with socat:

socat -u TCP4-LISTEN:4444,reuseaddr,fork OPEN:/tmp/log.txt,creat,append

It will listen on tcp port 4444, it can accept multiple simultaneous connections which guarantees no connection is refused and it will write the data recieved on the port to /tmp/log.txt, appending to the file if it already exists or creating a new if it does not.