Sometimes you might have to activate some interfaces in your Ubuntu Server (or desktop for that matter) that you could use for your VMWare server, or to do a tcpdump for some promiscious traffic coming from a mirrored port…or hell’s bells, whatever…you just need it active without any IP assigned – and you need it to be up even if the box restarts.
If you want to do it, here’s how …
1. Open the /etc/network/interfaces file with your favourite editor – vim in my case (remember to make a backup first – always be safe)
sudo vim /etc/network/interfaces
2. Add the following lines (replace eth1 with your applicable interface)
auto eth1 iface eth1 inet manual up ifconfig eth1 up
3. Write, quit and restart your networking
sudo /etc/init.d/networking restart
If all was done correctly, and assuming the interface was also named eth1, you should now have the extra interface available, without a DHCP or statically assigned IP Address.
You can use the following command to check, but if you got here I think you already know that