peiffer at umn.edu
Tue Apr 28 12:13:56 UTC 2009
Glenn Satchell wrote:
>> Date: Tue, 28 Apr 2009 13:17:36 +0300
>> From: William Jobs <wllmjbs at gmail.com>
>> I'd also appreciate it if someone could let me know, if I'm attempting
>> something that is just not possible. That way I could stop banging my head
>> against the wall :)
>> On Tue, Apr 28, 2009 at 12:49 PM, William Jobs <wllmjbs at gmail.com> wrote:
>>> Hi all,
>>> I've been trying out ISC's dhcp software as a relay server and everything
>>> is working fine except for the remote-id sub-option of Option 82. For some
>>> reason dhcrelay will not include this sub-option in the packets it forwards
>>> to the DHCP server. I get the circuit-id sub-option, just fine.
>>> Is there a specific way to enable this feature? I'm currently running
>>> dhcrelay as follows for debugging purposes:
>>> dhcrelay -d -a 10.0.0.1
>>> Any help would be appreciated.
> Which version of dhcrelay and dhcpd are you using? What platform? (linux, *bsd,
> solaris, hp and so on...)
> This is from the 4.1.1b1 dhcrelay man page, note the last sentence.
> -a Append an agent option field to each request before
> forwarding it to the server. Agent option fields in
> responses sent from servers to clients will be stripped
> before forwarding such responses back to the client.
> The agent option field will contain two agent options:
> the Circuit ID suboption and the Remote ID suboption.
> Currently, the Circuit ID will be the printable name of
> the interface on which the client request was received.
> The client supports inclusion of a Remote ID suboption
> as well, but this is not used by default.
> This is the equivalent section from the 3.1.1 dhcrelay man page.
> If the -a flag is set the relay agent will append an agent
> option field to each request before forwarding it to the
> server. Agent option fields in responses sent from servers
> to clients will be stripped before forwarding such responses
> back to the client.
> The agent option field will contain two agent options: the
> Circuit ID suboption and the Remote ID suboption.
> Currently, the Circuit ID will be the printable name of the
> interface on which the client request was received. The
> client supports inclusion of a Remote ID suboption as well,
> but this is not used by default.
> So it seems the remote-id is not added by default. The remote-id is
> mentioned in the source, but there is no way to set it. Looks like if
> the packet arrives with a remote-id then the remote-id will not be
I don't run the dhc relay code, so I am not an authority there, but
there is also the '-A <size>' option to consider:
It is recommended that with the Internet Systems Consortium
server, the maximum packet size be set to about 1400, allowing
of extra space in which the relay agent can put the agent
field, while still fitting into the Ethernet MTU size. This
done by specifying the -A flag, followed by the desired maximum
size (e.g., 1400).
So dhcrelay -a -A 1400 -d 10.0.0.1 ??
> Sorry it's not much use to you...
> dhcp-users mailing list
> dhcp-users at lists.isc.org
Network Support Engineer
Office of Information Technology
University of Minnesota/NorthernLights GigaPOP
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