C'est deja ce que je faisais avec le FGS202
Dans mon dhclient.conf
option rfc3442-classless-static-routes code 121 = array of unsigned integer 8;
option user-class code 77 = string;
option authsend code 90 = string;
send vendor-class-identifier "sagem";
send user-class 2b:46:53:56:44:53:4c:5f:6c:69:76:65:62:6f:78:2e:49:6e:74:65:72:6e:65:74:2e:73:6f:66:74:61:74:68:6f:6d:65:2e:4c:69:76:65:62:6f:78:34;
send authsend 00:00:00:00:00:00:00:00:00:00:00:1a:09:00:00:05:58:01:03:41:01:0d:66:74:69:2f:72:XX:XX:XX:XX:XX:XX;
#send dhcp-client-identifier 01:a4:3e:51:65:e7:86;
request subnet-mask, routers,
broadcast-address, dhcp-lease-time, dhcp-renewal-time, dhcp-rebinding-time;