I recently changed the operating system of my server from FC6 to FreeBSD6, I am using Plesk as control panel.

when I try to add ip addresses in Plesk, I add in this format:

69.11.111.11/255.255.255.248

the first two ip addresses is fine, I can add network mask 255.255.255.248, but when I add the third ip address, it will change the second ip address's network mask to 255.255.255.255. in result all my websites on the server are really really slow.

why this is happening? is that because the operating system has change, I have to change the network mask too? I did the same thing in FC6, it works fine, why doesn't work in FreeBSD?

Please Help !!!