Option 61 (Client ID) in DHCPOFFER
Laurent PROUFF
lprouff at auchan.fr
Mon Nov 28 08:14:58 UTC 2011
Hello,
As it is mentioned in the draft from the link you gave, RFC2131 states
that client identifier *MUST NOT* be returned by dhcp server, so here is
the answer to your question.
I don't think the behavior proposed from this draft (that cid *MUST* be
included) has already been implemented in ISC DHCP (draft dated 16/08/2011).
regards,
laurent
2011/11/25 Dima Fadeyev <dima at scancom.es>
>
> Tested and I have same result (even asking the client to claim it).
>
> I think, from my knowledge, that cid (opt 61) is only valuable for dhcp
> server (why the client asks the server for things it already knows). Do you
> have specials needs for doing this ?
>
> I'm testing the GPON OLT/ONTs from one asian manufacturer. The
> manufacturer is saying that the ONT (CPE equipment) monitors the 61 option
> in dhcpoffers to tell if the dhcpoffer is destinated to this particular ont
> or to some other device.
>
> In other words, the ONT would send a dhcpdiscover with a unique option 61
> and monitor for a dhcpoffer which would have the same value set in this
> option. Once such a dhcpoffer is seen, the ONT would accept the IP and
> other relevant data set in dhcpoffer.
>
> The manufacturer have given me this reference
> http://tools.ietf.org/html/draft-ietf-dhc-client-id-01
> saying that in part three it is stated that the client identifier must be
> included in dhcpoffer if it is included in dhcpdiscover by client. They've
> also given me the name of dhcp server they are using (and which is
> inserting the option 61 in dhcpdiscover): N2X (Agilent Test Machine), which
> I've never heard of before.
>
>
> One possible way could be to send back value via a private option (range
> 224-254) :
>
> option cid-sent-back code 224 = string;
> option cid-sent-back = option dhcp-client-identifier;
> option dhcp-parameter-request-list 1,3,6,12,15,26,28,42,224;
>
> regards,
> laurent
>
>
> 2011/11/24 Dima Fadeyev <dima at scancom.es>
>
>> Thanks for your reply,
>>
>> I've included this line into my dhcpd.conf:
>> option dhcp-parameter-request-list 1,3,6,12,15,26,28,42,61;
>>
>> As you can see, option 61 is included. However I still can't make dhcp
>> server include the option 61 into dhcpoffer. This is how my dhcpdiscover
>> and dhcpoffer packets look like right now:
>>
>> On 11/23/2011 08:21 PM, Laurent PROUFF wrote:
>> TIME: 16:00:11.283846
>> IP: > (00:d0:cb:cf:d0:ab) > (Broadcast)
>> OP: 1 (BOOTPREQUEST)
>> HTYPE: 1 (Ethernet)
>> HLEN: 6
>> HOPS: 0
>> XID: 64217936
>> SECS: 0
>> FLAGS: 0
>> CIADDR: 0.0.0.0
>> YIADDR: 0.0.0.0
>> SIADDR: 0.0.0.0
>> GIADDR: 0.0.0.0
>> CHADDR: 00:d0:cb:cf:d0:ab:00:00:00:00:00:00:00:00:00:00
>> SNAME: .
>> FNAME: .
>> OPTION: 53 ( 1) DHCP message type 1 (DHCPDISCOVER)
>> OPTION: 61 ( 7) Client-identifier 01:00:d0:cb:cf:d0:ab
>> OPTION: 60 ( 11) Vendor class identifier udhcp 1.9.2
>> OPTION: 57 ( 2) Maximum DHCP message size 576
>> OPTION: 55 ( 8) Parameter Request List 1 (Subnet mask)
>> 3 (Routers)
>> 6 (DNS server)
>> 12 (Host name)
>> 15 (Domainname)
>> 26 (Interface MTU)
>> 28 (Broadcast address)
>> 42 (NTP servers)
>>
>>
>> ---------------------------------------------------------------------------
>> TIME: 16:00:11.284036
>> IP: > (00:22:4d:38:37:27) > (00:d0:cb:cf:d0:ab)
>> OP: 2 (BOOTPREPLY)
>> HTYPE: 1 (Ethernet)
>> HLEN: 6
>> HOPS: 0
>> XID: 64217936
>> SECS: 0
>> FLAGS: 0
>> CIADDR: 0.0.0.0
>> YIADDR: 10.0.0.154
>> SIADDR: 0.0.0.0
>> GIADDR: 0.0.0.0
>> CHADDR: 00:d0:cb:cf:d0:ab:00:00:00:00:00:00:00:00:00:00
>> SNAME: .
>> FNAME: .
>> OPTION: 53 ( 1) DHCP message type 2 (DHCPOFFER)
>> OPTION: 54 ( 4) Server identifier 10.0.0.32
>> OPTION: 51 ( 4) IP address leasetime 340600 (3d22h36m40s)
>> OPTION: 1 ( 4) Subnet mask 255.255.255.0
>> OPTION: 3 ( 4) Routers 10.0.0.2
>> OPTION: 6 ( 8) DNS server 10.0.0.2,8.8.8.8
>> OPTION: 12 ( 7) Host name foobar2
>> OPTION: 15 ( 11) Domainname example.com
>> OPTION: 26 ( 2) Interface MTU 1500
>> OPTION: 28 ( 4) Broadcast address 10.0.0.255
>> OPTION: 42 ( 4) NTP servers 10.0.0.32
>>
>> Best regards,
>> Dima Fadeyev
>>
>> hello,
>>
>> maybe it can help.... (from man dhcp-options)
>>
>> *option dhcp-parameter-request-list* *uint16* [*,* *uint16*... ]*;* This
>> option, when sent by the client, specifies which options the client wishes
>> the server to return. Normally, in the ISC DHCP client, this is done
>> using the *request* statement. If this option is not specified by the
>> client, the DHCP server will normally return every option that is valid in
>> scope and that fits into the reply. When this option is specified on the
>> server, the server returns the specified options. This can be used to force
>> a client to take options that it hasn't requested, and it can also be used
>> to tailor the response of the DHCP server for clients that may need a more
>> limited set of options than those the server would normally return.
>> regards, laurent
>>
>> 2011/11/23 Dima Fadeyev <dima at scancom.es>
>>
>>> Hello everyone,
>>>
>>> I have a quick question. Is it possible to make ISC dhcpd server insert
>>> the option 61 (client id) in DHCPOFFER, in case if it is present in
>>> DHCPDISCOVER?
>>> The ISC dhcpd version we are using is dhcp-4.1.1
>>> (dhcp-4.1.1-12.P1.el6_0.4.x86_64 CentOS rpm).
>>>
>>> Thanks in advance
>>>
>>> --
>>> Dima Fadeyev
>>>
>>> _______________________________________________
>>> dhcp-users mailing list
>>> dhcp-users at lists.isc.org
>>> https://lists.isc.org/mailman/listinfo/dhcp-users
>>>
>>
>>
>>
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>
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>
>
> --
> Dima Fadeyev
> Departamento de Ingeniería de Scancom S.L.
>
>
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