[CONFIGURATION] How to: Static IP (for home router)

[TwoFistedJustice]

I have two laptops that I want to be able to ssh back and forth from on my home router. It really helps to have a predictable (static) IP address on the LAN for this. So I figured it out. And here's my notes on how I done it. I'm running Kubuntu 22.04 but I think it will be very similar if not the exact same on other versions in the same general release time frame.


Setting up a static IP in Kubuntu 22.04 (and probably others too)

Useful URLs

Check which ports are open:
https://www.cyberciti.biz/faq/unix-l...n-use-command/


Many commands and how to use
https://www.cyberciti.biz/faq/unix-l...in-use-command


Control UFW by CLI
https://www.cyberciti.biz/faq/how-to...ntu-20-04-lts/


Using Network Manager CLI to set up static IP
https://linux.fernandocejas.com/docs...tic-ip-address


What you will need

• The UUID of the LAN connection on your computer
• Your IP on the LAN
• The subnet on the LAN
• The Gateway address of the LAN
• DNS server address for the LAN

get the UUID

$ nmcli connection show

or

$ nmcli con show

- console output -
NAME UUID TYPE DEVICE
Home-wifi egd6cdd8-8ewd-8bf8-a0fd-cjkhkiu34f1e wifi wlp3s0
Starbucks WiFi 24181ab4-6f1d-446b-a350-f6b123xyzu94 wifi --
Wired connection 1 b92e3a8a-d798-3bff-ae0d-9f1abc123ea4 ethernet --


To get your IP

$ hostname -I

( upercase i )


to get your subnet

$ ifconfig

Look for your IP, subnet follows, looks like 255.255.255.0
Count the quantity of 255
Multiply the quantity by 8
your subnet is forward slash that number
in this example:
3 x 8 = 24
subnet = /24

to get the LAN gateway address

$ ip r | grep default

looks like:
default via 192.168.62.1 dev wlp4s0 proto dhcp metric 600

The gateway in this example is: 192.168.62.1

to get the DNS address for the LAN
Not sure. try 1.1.1.1

$ resolvectl status

pulls up the DNS you are using on the www

$ cat /etc/resolv.conf

shows your computer's dns


Setting the static IP address
- Note: the values in this section are all made-up example values and may not work IRL. You have to find your own actual values.


The basic command syntax is the same for each step, may require sudo

nmcli con modify [UUID] ipv4.[name of thing you want to change] [value you want to set]

- "con" is short for "connection" - either will work. I show "connection" below to make it easier to read and remember

In this case I will set a static IP for my home wifi.
I want a static IP address of 192.168.69.007 (because I'm really a British super-spy)

set IP address AND /subnet mask

$ nmcli connection modify egd6cdd8-8ewd-8bf8-a0fd-cjkhkiu34f1e ipv4.addresses 192.168.69.007/24

set Gateway address

$ sudo nmcli connection modify egd6cdd8-8ewd-8bf8-a0fd-cjkhkiu34f1e ipv4.gateway 192.168.1.1

set DNS

$ sudo nmcli connection modify egd6cdd8-8ewd-8bf8-a0fd-cjkhkiu34f1e ipv4.dns 1.1.1.1

set Method

$ sudo nmcli connection modify egd6cdd8-8ewd-8bf8-a0fd-cjkhkiu34f1e ipv4.method manual

- Note: "manual" is the actual value you want for a static ip.

Activate the connection

$ sudo nmcli connection up [UUID]

Check your work

$ sudo cat /etc/NetworkManager/system-connections/[network name].nmconnection​