Re: [dhcwg] WGLC on draft-ietf-dhc-relay-port-02 - respond by Apr 26

"Naiming Shen (naiming)" <> Fri, 07 April 2017 00:15 UTC

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From: "Naiming Shen (naiming)" <>
To: Ted Lemon <>
CC: Tomek Mrugalski <>, dhcwg <>
Thread-Topic: [dhcwg] WGLC on draft-ietf-dhc-relay-port-02 - respond by Apr 26
Date: Fri, 7 Apr 2017 00:15:22 +0000
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Subject: Re: [dhcwg] WGLC on draft-ietf-dhc-relay-port-02 - respond by Apr 26
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Hi Ted,

In section 4.1 “Source Port Sub-option for DHCPv4", it says:

   When a DHCP server receives a message from a relay agent with the
   "Source Port Sub-option", it MUST remember the UDP source port of the
   message and use that port number as the UDP destination port when
   sending the reply message to the same relay agent.

In section 4.2 “Source Port Sub-option for DHCPv6", it says:

   When a DHCPv6 server receives a Relay-forward message with the "Relay
   Source Port Option", it MUST copy the option when constructing the
   Relay-reply chain in response to the Relay-forward message.  This
   option MUST NOT appear in any message other than a Relay-forward or
   Relay-reply message.  Additionally, the DHCPv6 server MUST check and
   use the UDP source port from the UDP packet of the Relay-forward
   message in replying to the relay agent.

thus the dhcp server behavior for both v4 and v6 is defined.

Best Regards,
- Naiming

> On Apr 6, 2017, at 5:03 PM, Ted Lemon <> wrote:
> No, that's not quite what I mean.   What I mean is that you have to explicitly say what the DHCP server does.   Right now I'm not seeing that.    Maybe I missed it—I read the document pretty quickly.
>> On Apr 6, 2017, at 5:02 PM, Naiming Shen (naiming) <> wrote:
>> Hi Ted,
>> Thanks for the suggestion. Currently in section 6 “Compatibility”, it says:
>>    It is recommended to upgrade the server side first before using a non-DHCP
>>    UDP port for a relay agent.
>> How about changing to this:
>>   The DHCP server MUST be upgraded to support the extension specified
>>   in this document before the extension is used by a relay agent.