Hostname and domainname required

conf t

hostname $HOSTNAME
ip domain-name $DOMAINNAME

crypto key generate rsa modulus 2048
ip ssh version 2

line vty 0 15
! Only SSH
! transport input ssh

! Allow SSH and telnet
! transport input ssh telnet

! Allow ALL
transport input all

Domain services

conf t
ip name-server server1 server2 ... server6
ip domain lookup