I just had a new modem installed (Surfboard 4100) because my previous one (3COM "Sharkfin) became defective. Ever since I got the new modem from my ISP I've been unable to obtain a DHCP lease through ...

Convert it from hex to decimal, and you have the number of seconds after 7pm, Dec. 31, 1969 that your DHCP lease expires. Using the date command to translate this into an actual date (as suggested by ...