rejecting an IP address from IPCP

00:12:01: Vi2 IPCP: I CONFREQ [REQsent] id 1 len 10
00:12:01: Vi2 IPCP: Address 61.24.201.139 (0x03063E19CA8A)
00:12:01: Vi2 IPCP: O CONFACK [REQsent] id 1 len 10
00:12:01: Vi2 IPCP: Address 61.24.201.139 (0x03063E19CA8A)
00:12:01: Vi2 IPCP: I CONFNAK [ACKsent] id 1 len 10
00:12:01: Vi2 IPCP: Address 85.63.7.230 (0x0306544008E7)
00:12:01: Vi2 IPCP: O CONFREQ [ACKsent] id 2 len 10
00:12:01: Vi2 IPCP: Address 85.63.7.230 (0x0306544008E7)
00:12:01: Vi2 IPCP: I CONFACK [ACKsent] id 2 len 10
00:12:01: Vi2 IPCP: Address 85.63.7.230 (0x0306544008E7)
00:12:01: Vi2 IPCP: State is Open
00:12:01: Di2 IPCP: Install negotiated IP interface address 85.63.7.230

Hi, I was just looking at the above output from the dubug ppp commands. I'd quite like to be able to reject a particular IP, eg the one above

85.63.7.230. Is there anything I can do to make a dialer interface reject an IP? I've tried setting it on a loopback address thinking that it might reject it then but it doesn't.

Any ideas big brains?