sonic-buildimage/files/dhcp/dhclient.conf

# Configuration file for /sbin/dhclient, which is included in Debian's
#       dhcp3-client package.
#
# This is a sample configuration file for dhclient. See dhclient.conf's
#       man page for more information about the syntax of this file
#       and a more comprehensive list of the parameters understood by
#       dhclient.
#
# Normally, if the DHCP server provides reasonable information and does
#       not leave anything out (like the domain name, for example), then
#       few changes must be made to this file, if any.
#

option rfc3442-classless-static-routes code 121 = array of unsigned integer 8;
option snmp-community code 224 = text;
option minigraph-url code 225 = text;
option acl-url code 226 = text;

send host-name = gethostname();
request subnet-mask, broadcast-address, time-offset, routers,
        domain-name, domain-name-servers, domain-search, host-name,
        dhcp6.name-servers, dhcp6.domain-search, interface-mtu,
        rfc3442-classless-static-routes, ntp-servers, 
        snmp-community, minigraph-url, acl-url;