RZG1M doesn't not reflect it's hostname

When I connected the board to router ,the router gets only it's MAC address rather it's hostname.So, I added DHCP package to image and changed the dhcpclient.conf file under /etc/dhcp/ i.e uncommenting the 'send host-name " "; ' .Even after uncommenting it, hostname is not reflected in the router .Can anyone help me with this ?

Thanks in advance

Regards,

Chetan