IPv6 ICMP multicast response
Martin Petraschek
petraschek at ftw.at
Thu Apr 7 07:18:33 PDT 2005
On 07 Apr 2005 09:30:29 -0400, Lowell Gilbert wrote:
>"Martin Petraschek" <petraschek at ftw.at> writes:
>
>> By default, FreeBSD does not reply to ICMP multicast echo
>>requests. For IPv4 this behaviour can be changed with
>>
>> sysctl net.inet.icmp.bmcastecho=0|1
>>
>> Is there a similar control for IPv6?
>
>No. That would violate RFC 2463, section 2.4(e.2).
>As well as being a bad idea.
The section you are referencing in RFC 2463 is concerning ICMP
ERROR messages. Echo requests/responses are informational
messages, therefore this section does not apply.
The same RFC 2463, section 4.2 states:
An Echo Reply SHOULD be sent in response to an Echo
Request message sent to an IPv6 multicast address. The
source address of the reply MUST be a unicast address
belonging to the interface on which the multicast Echo Request
message was received.
Therefore, the OS _should_ respond to a multicast echo request!
Martin
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