# Header Your content here
Measure temperature natively on Ubuntu: `paste <(cat /sys/class/thermal/thermal_zone*/type) <(cat /sys/class/thermal/thermal_zone*/temp) | column -s $'\t' -t | sed 's/\(.\)..$/.\1°C/'`
Should give you something like: `cpu-thermal 67.6°C`
IP address on WAN: `192.168.1.191` User: `ubuntu`
Motivation: - QNAP security notification, but unable to update firmware, probably from all the fiddling. - Exposing HTTP port can be dangerous.
Prerequisites: - Raspberry Pi Model 4B - Card reader + SD card - Male micro-HDMI to female HDMI adapter - HDMI cable
---
# Installing Ubuntu on Raspberry Pi
Using Raspberry Pi Imager to install Ubuntu Server 20.04 LTS. This is a required read for setup instructions:
https://ubuntu.com/tutorials/how-to-install-ubuntu-on-your-raspberry-pi
In particular, need to set Wi-Fi credentials in `(system-boot)/network-config`:
``` wifis:
wlan0:
dhcp4: true
optional: true
access-points:
<wifi network name>:
password: "<wifi password>"
```
Not really working for me, but you can still connect an Ethernet cable and access it remotely.
Useful things you should already know:
``` screen # multiple windows Ctrl-A + Esc # enter copy mode for scrolling ```
Useful server information commands, from: https://opensource.com/article/20/12/linux-server
``` uptime # server uptime and current users who # current users grep sh$ /etc/passwd # who can access, regex grep lscpu # list CPU, alt "cat /proc/cpuinfo" lsmem # list memory, alt "cat /proc/meminfo" lshw # list hardware attached ps -f # snapshot of current processes, -e for all processes lsof # list open files iptables -L # iptable forwarding ss -tupan # sockets, replace netstat dmesg # device logs journalctl | tail # view systemd journal ```
Stuff to install on Pi:
``` net-tools # ifconfig ```
Package management:
``` sudo apt update && sudo apt upgrade -y ```
Useful starting:
https://www.digitalocean.com/community/tutorials/initial-server-setup-with-ubuntu-20-04 https://www.howtogeek.com/177621/the-beginners-guide-to-iptables-the-linux-firewall/
``` adduser <username> usermod -aG sudo <username> ```
Firewall, start with UFW to understand what rules need to be done, then manage using the more low-level iptables:
``` ufw allow OpenSSH sudo ufw allow from 192.168.0.0/16 to any port 22 sudo ufw allow from 10.8.0.0/16 to any port 22 sudo ufw allow 443 sudo ufw allow 80 ufw enable ufw status # see rules ufw allow ```