Show ARP table: ip neigh show

# Switch to root mode:
sudo su

https://help.ui.com/hc/en-us/articles/204960094-EdgeRouter-Configuration-and-Operational-Mode

Some great shortcuts from here: https://www.reddit.com/r/Ubiquiti/comments/9dwok0/edgerouter_cli_guide_quick_and_concise_howto_with/

terminal length 0 will show all the output without segmenting them, so you don't have to press spacebar to see the next page.

show configuration will show how the router is configured.

show configuration commands will show all the commands to reconfigure the router to exactly how it currently is. This is useful if you log the printable output in Putty, so you can copy/paste the commands later, or even edit them in a text file and then paste them into the router.

configure enter configuration mode where you can make changes to the router. When you're inside this mode, you can type show and it'll be equivalent to type show configuration. You can type exit to leave this mode.

commit will apply the changes you've made.

save will save the changes so they're reflected upon reboot. This is useful to omit if you want to test the router with commit changes, and if it breaks something, a simple reboot will bring it back to the previous config.

; allows you to chain commands together. Example: commit;save;exit will execute those 3 in order.

? will show all available commands in the current context. Example: if I type set ? it will display all the possible things I can set/change. If I type set interfaces ? it will show all the interfaces that I can set/change. So on and so forth. It's a great way to figure out where things are and how they're set, etc.

TAB will autofill the rest of whatever commands are available. Example, if I type set inteTAB it'll autofill to set interfaces.

One way to think of the CLI is a bunch of sub-directories as you go through them. Example, let's say I want to change the description of eth0 port to 'my wan'.

set interfaces ethernet eth0 description 'my wan'
set indicates I'm going to add or change something; set something.

interfaces means I want to change one of the interfaces. Again, think of it like a directory: I'm going to look into the interfaces folder.

ethernet which interfaces do I want to set? The ethernet interfaces. Go into the ethernet folder.

eth0 which ethernet interface? eth0

description what do I want to change? The description.

'my wan' the quotations are needed for anything >1 word.

Keep in mind you can type ? anywhere along the commands to find out what the next "folder"/context command is. Example: if I type set interfaces ethernet ? it will show all the ethernet interfaces that are available.



Check error logs:
show log | grep openvpn



# Debugging
### Server process running? Also, check the cmd-line args.
ps -ef | grep openvpn
### openvpn logs via syslog
tail /var/log/messages
### ERL specific command
show openvpn status server
show openvpn status client
show ip route