Networking

Ubuntu basics

To see network details:

ip a

Bring an interface up/down:

sudo ifconfig enp4s0 down
sudo ifconfig enp4s0 up

DNSMasq

I disabled systemd and use dnsmasq for bitpost routing.

It provides static IPs to LAN via MAC addresses.

It performs DNS caching. Use /etc/resolv.conf to set up fallback DNS.

Update to new ISP

I did this for google fiber on 2022/09/30.

• Set up new ISP while keeping old
• Update any ethernet cables and NIC cards; I need cat6 from google fiber router GRAY port (2Gbps); I ordered a 10G network card on Amazon, not here yet.
• Remove old ISP cable from RJ45, plug in new ISP cable
• ssh 192.168.22.1 to get a terminal to bitpost box
• check that a new IP was obtained via `ip a`
• RESTART THE FIREWALL, it MUST BE STARTED after the IP is obtained! This was the kicker that had me scratching my head for an hour.

sudo su -
edit_firewall
# Ctrl-D to save and exit and restart it

• Check that you can ping google.com; check that LAN is up and ready
• Go update ALL domains.google.com DNS records with the new IP!
• Pray for IP stability! reddit commentors gave me hope, we will see...

Force apt to use a proxy

Edit /etc/apt/apt.conf:

Acquire::http::Proxy "http://myproxy.com:####";