[159493] in North American Network Operators' Group
Re: Question about DOCSIS DHCP vs ARP
daemon@ATHENA.MIT.EDU (Jean-Francois Mezei)
Fri Jan 11 20:29:36 2013
Date: Fri, 11 Jan 2013 20:29:23 -0500
From: Jean-Francois Mezei <jfmezei_nanog@vaxination.ca>
To: nanog@nanog.org
In-Reply-To: <9730DC3EEB7574499C9D94133B7EAB39093511EA@CL07MBA.rci.rogers.ca>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On 13-01-11 19:59, Karl Brumund wrote:
> JF,
>
> Long ago been fixed. Look at Cisco CMTS config documentation, particularly cable-source-verify.
Many thanks. In particular, you need "cable-source-verify dhcp" to
prevent self assigned IPs that are unused by neighbours.
Is this something that is now basically a default for all cable
operators ? Or does this command add sufficient load to the CMTS that
some cable operators choose to not use it for performance purposes ?
What happens when a CMTS reboots and has an enpty database of DHCP
leases ? Does it then query the DHCP server for every IP/MAC it sees
that it doesn't yet know about ?
