I requested two additional IP addresses from my host and this is the response they gave:

"xxx.168.118.188/30 which should give you 2-4 depending on os"

I 'xxx' the first 3 numbers, but I dont get this. At first I thought the IP's were:
xxx.168.118.188 and
xxx.168.118.30 but they dont work after adding them to my network interface, am I missing something obvious here?

And what does '2-4 depending on operating system' mean?

Hi,

The /30 indicates the number of network bits, which you can work your subnet mask out from (255.255.255.252)

xxx.168.118.188 <- that is your network address, and now you have your subnet mask, you can work out your extra IP's.

With a subnet mask of 255.255.255.252, and a network address of xxx.168.118.188 your broadcast is: xxx.168.118.191

Therefore your usable IP's are: xxx.168.118.189, and xxx.168.118.190

Steve

The /30 is a subnet mask.

For more information,
http://www.tangent.org/~brian/dict/subnet.html