Problem in receiving vendor-encapsulated-options, other standard options are received

[glenn.satchell at uniq.com.au]

Hi Rajeev

The server dhcpd.conf looks mostly right, but I am not sure about 
setting

option vendor-class-identifier "MAGNUM-CL-VCI";

Usually this is set on the client to tell the server which vendor the 
client is. See the reference in the dhcp-options man page.

So I would try sniffing the network packets to see if the vendor 
encapsulated options are being sent, eg using tcpdump. Then at least you 
know whether to focus on the server or the client.

Second step would be to comment out the option vendor-class-identifier 
statement and see what, if any, difference that makes to the packet 
trace.

Third you could try adding

option vendor-class-identifier "MAGNUM-CL-VCI";

to the client config file to see if that makes any difference.

regards,
Glenn

On 2022-11-09 22:44, rajeev Gaur wrote:
> Hello All
> 
> I am facing a situation here regarding receiving
> vendor-encapsulated-options at client end.
> 
> Client: Internet Systems Consortium DHCP Client 4.2.5
> 
> Server: Internet Systems Consortium DHCP Server 4.2.5
> 
> OS: CentOS Linux release 7.9.2009 (Core) (Same at client and server
> systems)
> 
> Server Side config: /etc/dhcp/dhcpd.conf
> 
> #
> 
> # DHCP Server Configuration file.
> 
> #   see /usr/share/doc/dhcp*/dhcpd.conf.sample
> 
> #
> 
> authoritative;
> 
> option space MAGNUM-CL-INFO code width 1 length width 1 hash size 7;
> 
> option MAGNUM-CL-INFO.client-ip code 1 = ip-address;
> 
> option MAGNUM-CL-INFO.client-port code 9 = unsigned integer 16;
> 
> subnet 192.168.1.0 netmask 255.255.255.0 {
> 
>        range 192.168.1.171 192.168.1.180;
> 
>        option routers                   192.168.1.156;
> 
>        option subnet-mask               255.255.255.0;
> 
>        option domain-name-servers 8.8.8.8;
> 
>        default-lease-time 100;
> 
>        max-lease-time 100;
> 
>        option host-name "server-77";
> 
>        option ntp-servers 10.23.45.11;
> 
>        option vendor-class-identifier "MAGNUM-CL-VCI";
> 
>         vendor-option-space MAGNUM-CL-INFO;
> 
>          option MAGNUM-CL-INFO.client-ip 192.168.122.150;
> 
>          option MAGNUM-CL-INFO.client-port 31080;
> 
> }
> 
> Client side config: /etc/dhcp/dhclient-eth0.conf
> 
> 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,
> 
> netbios-name-servers, netbios-scope, interface-mtu, ntp-servers;
> 
> ifdown eth0;
> 
> ifup eth0;
> 
> Steps followed:
> 
> 	* Started DHCP Server and I can see, server listening on interface
> with subnet 192.168.1.0.
> 	* Started the client with following command:
> 
> [/sbin/dhclient -H localhost -1 -q -lf
> /var/lib/dhclient/dhclient—eth0.lease -pf /var/run/dhclient-eth0.pid
> eth0]
> 
> I understand this is long command and all the parameters are not
> required, but to give our own pid and lease find we are giving it like
> this.
> 
> 	* On execution of command I can see DISCOVER reaching the server and
> server responding with OFFER, then REQUEST and ACK.
> 	* I can see the lease file getting generated at this path:
> [/var/lib/dhclient/dhclient-<UUID>-eth0.lease]. The lease file looks
> like this:
> 
> lease {
> 
>   interface "eth0";
> 
>   fixed-address 192.168.1.171;
> 
>   option subnet-mask 255.255.255.0;
> 
>   option routers 192.168.1.156;
> 
>   option dhcp-lease-time 100;
> 
>   option dhcp-message-type 5;
> 
>   option domain-name-servers 8.8.8.8;
> 
>   option dhcp-server-identifier 192.168.1.156;
> 
>   option ntp-servers 10.23.45.11;
> 
>   option host-name "server-77";
> 
>   renew 5 2022/11/04 09:08:33;
> 
>   rebind 5 2022/11/04 09:09:20;
> 
>   expire 5 2022/11/04 09:09:33;
> 
> }
> 
> Problem:
> 
> I am not getting the vender encapsulated options, the hex TLV for
> options MAGNUM-CL-INFO.client-ip and MAGNUM-CL-INFO.client-port in
> lease file. There are other vendor options also but just showing two
> items as example config. Also, importantly, I have similar setups
> running at two other clients and that is running fine with all the
> steps informed above. But somehow, it is not working on this one.
> 
> One more point, if I add vendor-class-identifier in client conf, I
> receive it in lease file, but I am not receiving vendor encapsulated
> options.
> 
> Please suggest where am I going wrong.
> 
> Thanks
> 
> Rjv