BOOTP won't be transfered across a PPP link prior to setting up the link.

i.e. if a PC dials in and wants to get it's ip-address using BOOTP, usually a host on the network would have a MAC address = IP address table (bootptab).

The Access Server won't/can't forward the query out to the network during negotiation. So either the PC knows it's address or it takes it from the Access server.

With SLIP we respond from the A/S to the PC but do not go out to a host, so the SLIP Ip-address is actually taken from the port and isn't linked to the MAC address in any bootptab file on a host..

So...we can't use BOOTP or DHCP to assign a port based on MAC address to a remote PC across a PPP link.