Adding IPs address on the fly
You can quickly add an IP address on the terminal by doing:
ip addr add <ip> dev <interface>
For exapmle:
ip addr add 10.10.100.7 dev eth0
This can come in handy for quick tests (testing vhosts or plain network tests)
The same applies for IPv6 address:
ip -6 addr add <ipv6address>/<prefixlength> dev <interface>
Exapmle:
ip -6 addr add 2001:0db8:0:f101::1/64 dev eth0
You can test if your new ipv6 works by pinging one of google's IPv6 servers: ping6 -I eth0 2a00:1450:4001:80e::1006