Network Info

hostname -f                         # fully-qualified hostname
ifconfig -a                         # interfaces, MACs, IPs
ip a                                # where ifconfig is deprecated
which nc                            # is netcat installed?
netstat -tulpn | less               # current connections and listeners
cat /var/log/messages | grep DHCP   # DHCP traffic

One-stop dump (needs parsing):

cat /proc/net/* | less