man dhclient.conf
...
There is a variety of data contained in offers that DHCP servers send
to DHCP clients. The data that can be specifically requested is what
are called DHCP Options. DHCP Options are defined in
dhcp-options(5).
The request statement
request [ option ] [, ... option ];
The request statement causes the client to request that any server
responding to the client send the client its values for the specified
options. Only the option names should be specified in the request
statement - not option parameters. By default, the DHCP server
requests the subnet-mask, broadcast-address, time-offset, routers,
domain-name, domain-name-servers, host-name, nis-domain, nis-servers,
and ntp-servers options.
In some cases, it may be desirable to send no parameter request list at
all. To do this, simply write the request statement but specify no
parameters:
request;
...
Не включайте в этот список routers.