Is it possible to have multiple dhcp relay servers in line?
IOW DHCP client <=> DHCP Relay A <=> DHCP Relay B <=> DHCP server
Generally a DHCP relay is supposed to pick up a broadcast from a client and forward it to a specific server (read: unicast) address. Given that the packet sent by the relay to the server can be routed anywhere, the idea of cascading relays doesn't make a lot of sense. In practice it would be more likely to have some kind of intermediary DHCP server that derived pools from an upstream server.