Get the current NIC configuration (add the -6 switch for IPv6):
ip addr show
Get the current network routes (use -6 for IPv6):
ip route show
Run a port scan (TCP is the default protocol, use -sU for UDP):
nmap <hostname/ip> -p <port/port range/list of ports (coma separated)>
Ping/traceroute:
ping <server> # For IPv4 ping
traceroute <server> # For IPv4 traceroute
ping6 <server> # For IPv6 ping
traceroute6 <server> # For IPv6 traceroute
Name resolution:
host <server>
nslookup <server>
Check open ports:
ss -p -l -t | col # Replace –t for –u if you want UDP instead of TCP