RE: [dhcwg] Ports clarification on DHCPv6

["Andre Kostur" <akostur at incognito.com>]

Recall from draft-ietf-dhc-implementation-02 (RFC 2131 didn't specify a
source port, much like 3315):

        Relay agents should use port 67 as the source port number.
Relay 
        agents always listen on port 67, but port 68 has sometimes been
used 
        as the source port number probably because it was copied from
the 
        source port of the incoming packet. 

        Cable modem vendors would like to install filters blocking
outgoing 
        packets with source port 67.

Are we not going to run into the same considerations in the DHCPv6 world
where broadband ISPs (or I guess any ISP that relays their DHCP traffic)
will want to filter UDPv6 traffic with a source port of 547?  (Granted,
not an immediate concern as DHCPv6 penetration into the homes appears to
be non-existent currently.  But if we can nail this down before
widespread deployment, we may be able to avert some interoperability
issues.)

-----Original Message-----
From: Ralph Droms [mailto:rdroms at cisco.com] 
Sent: Thursday, December 07, 2006 11:29 AM
To: Andre Kostur; dhcwg at ietf.org
Subject: Re: [dhcwg] Ports clarification on DHCPv6

Working entirely from memory, the specification for the source port in
DHCPv4 is strictly based on the wording of RFC 2131, which, in turn, may
be
a carryover from BOOTP.  I don't believe that there is any functional
reason
why the source port needs to be constrained in DHCPv4.

We realized that the source port plays no real function in DHCP and we
explicitly did not specify source port behavior in RFC 3315.  Therefore,
there shouldn't be any implementation requirements that a DHCPv6
component
MUST use any particular source port.


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