Newby: unable to add new IP addresses

Hi, I have acquired the management of a friends website that uses PLESK. I haven't used PLESK before and need some help adding new IP addresses. My friends' host company has relocated her IP address and I need to add the new IP addresses to Plesk and remove the old, original ones. For example the two new IP addresses are 222.222.22.22 and 222.222.22.23. How do I enter these into the "IP address and subnet mask" field in "add IP address" in Plesk? I keep getting an error message whatever configuration I am using.

 

It depends on the configuration your ISP (the one that issued these IP addresses) is using, but in most cases it will be:

222.222.22.22/255.255.255.0
222.222.22.23/255.255.255.0