Using dhcpcd client to fetch vendor specific options

Sat Mar 11 19:42:30 UTC 2023

Hello Darren and All

Thank you for the response.
Yes you are correct, I need to use dhcp client to fetch vendor options
(option 43) items from DHCP Server.
Ok let me check how can I set option 55 Parameter Request List. But I was
not able to find it in dhcpcd man pages.
Let me search further on net.

Thanks
Rajeev

On Sat, Mar 11, 2023 at 10:15 PM Darren Ankney <darren.ankney at gmail.com>
wrote:

> Rje,
>
> If I understand correctly, you are wanting your DHCP client to fetch
> option 43 content from the server.  There should be a way, in dhcpcd,
> to modify option 55 (parameter request list) adding the vendor options
> (option 43) to the list of requested parameters.  Then the server will
> return the option 43 content.
>
> On Sat, Mar 11, 2023 at 2:29 AM rajeev Gaur <rajeev11gaur at gmail.com>
> wrote:
> >
> > Hello Sir
> >
> > I am working on a project for fetching various different categories of
> information from dhcp server.
> > DHCP Server: ISC DHCP Server 4.4.1
> > Client: dhcpcd 9.4.0, Compiled in features: INET ARP ARPing IPv4LL INET6
> DHCPv6 AUTH
> > Build environment: Yocto
> >
> > At this point when I am writing this mail, the basic working looks good.
> >
> > The DHCP server, starts stops restarts well. In logs I can see the
> DISCOVER / OFFER / REQUEST / ACK all working fine. Lease IP is properly
> provided to client.
> >
> > #
> >
> > # DHCP Server Configuration file.
> >
> > #   see /usr/share/doc/dhcp*/dhcpd.conf.sample
> >
> > #
> >
> >
> >
> > authoritative;
> >
> >
> >
> > option space  Vendor-ONAS-INFO code width 1 length width 1 hash size 5;
> >
> > option  Vendor-ONAS-INFO.ipadd code 1 = ip-address;
> >
> > option Vendor-ONAS-INFO.port code 9 = unsigned integer 16;
> >
> >
> >
> > subnet 192.168.2.0 netmask 255.255.255.0 {
> >
> >        range 192.168.2.35  192.168.2.52;
> >
> >        option routers                   192.168.2.56;
> >
> >        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 "OR-SERVER";
> >
> >        option ntp-servers 138.12.56.111;
> >
> >        option vendor-class-identifier "Vendor-ONAS";
> >
> >         vendor-option-space Vendor-ONAS-INFO;
> >
> >          option Vendor-ONAS-INFO.ipadd 192.168.71.50;
> >
> >          option Vendor-ONAS-INFO.port 11372;
> >
> > }
> >
> >
> > On the client side, dhcpcd, I have kept information to allow and deny
> interfaces, enabled the standard DHCP options for which I am getting values
> ( except for dhcp_client_identifier).
> > When I am performing ifdown and ifup for eth0 I am getting one leased IP
> from the dhcp server.
> >
> > #Use the hardware address of the interface for the Client ID
> > clientid
> > allowinterfaces eth0
> > denyinterfaces eth1
> >
> > option ntp_servers
> > option dhcp_server_identifier
> > option dhcp_client_identifier (**Not getting this output)
> >
> > My problem / Query:
> > 1) What option to give in dhcpcd.conf to fetch the vendor options that i
> have declared in dhcpd.conf at the server side.
> > 2) Do I need to enable any thing on any side (client or server).
> >
> > I did not see much documentation for dhcpcd client for vendor options.
> > I did saw the dhcpcd.conf man page for vendor information but it shows:
> > vendor code ,valueAdd an encapsulated vendor option. code should be
> between 1 and 254 inclusive. To add a raw vendor string, omit code but keep
> the comma. Examples. Set the vendor option 01 with an IP address.vendor
> 01,192.168.0.2Set the vendor option 02 with a hex code.vendor
> 02,01:02:03:04:05Set the vendor option 03 with an IP address as a
> string.vendor 03,\"192.168.0.2\"Set un-encapsulated vendor option to hello
> world.vendor ,"hello world"
> >
> > But I don't need to add any vendor option I have to fetch it from the
> server.
> >
> > I also tried giving vendorclassid so that it can fetch the details
> provided for the vendor class identifier in the server, but i don't see any
> output.
> >
> > I have previously worked with dhclient and i was able to fetch
> information using that and I also see it has much more documentation
> online. But i see less documentation for dhcpcd. But this is the only
> recommended client for Yocto build environment.
> >
> > Please suggest how can I fetch the vendor options using dhcpcd client.
> >
> > Thanks
> > Rje
> > --
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> >
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> --
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