I have Debian Wheezy with the latest patches and have checked the box to allow Network Configuration. I can add an IP to the server and it adds it just fine, but when I delete the IP it never removed it from the interface. I could have swore in the past it did remove the IP from the interface as well as add it thru ISPconfig. Am I confused or did it work that way before? Was moving stuff around this weekend and did not double check that the IP was really removed after having removed from ISPConfig and it was killing me trying to use that IP on another box. I ended up having duplicate IP's and that generated a little hair pulling until I realized that the ISPConfig box never released the IP so I had to modify /etc/network/interfaces manually and remove the IP.