On the SG300 & 500 I always seem to have issue with devices that have reserved IPs. It seems if I enter its MAC in the reservations table for some devices it won't receive the assigned IP until I remove the MAC and use a Client ID instead but on other devices if Use a client id in the table it won't recieve the proper IP until I remove the clent id and enter its MAC. When using dumber devices that only allow a MAC in their reservation tables it always used to work but on these switches it seems to be a crap shoot. Why?