VYOS

Configure interface

configure
set interfaces ethernet eth0 address 0.0.0.0/24
set interfaces ethernet eth0 address dhcp
commitc
save

DHCP

set service dhcp-server
set service dhcp-server shared-network-name LAN2 subnet 172.20.2.0/24 start 172.20.2.100 stop 172.20.2.200
set service dhcp-server shared-network-name LAN2 subnet 172.20.2.0/24 default-router 172.20.2.1
set service dhcp-server shared-network-name LAN2 subnet 172.20.2.0/24 dns-server 1.1.1.1
set service dhcp-server shared-network-name LAN2 subnet 172.20.2.0/24 domain-name lab.local

https://docs.vyos.io/en/latest/configuration/service/dhcp-server.html

SSH

set service ssh

Create user

set system login user lab authentication plaintext-password examplepassword
set system login user lab level admin
commit
save

Save config

Default

save

To file

save /opt/vyatta/etc/config.boot.default