Hello everybody, for my Case I needed to change one Octett of my NAS-IP-Address ( like from x.x.4.x to x.x.5.x )! I don't really found an function to change only one octett from the NAS-IP-Address, so I did it with Bit-Shifting ;) You could use the following Code Snipet in an C or C++ Module My Code looks so: VALUE_PAIR *vp; vp = pairfind(request->packet->vps,1); while(vp) { // Default Operations to Change the NAS-IP-Addres on certain value // if (...) ... VALUE_PAIR *state; state = pairfind(request->packet->vps, 4); if(state != NULL) { int octett = 77; struct in_addr addr; addr.s_addr = ((octett << 16) | (state->vp_ipaddr & 0xff00ffff)) // Change the third octett from the NAS-IP-Address to 77 state->data.ipaddr = addr; } { Greetz Patrick