nanog mailing list archives

Re: IPv6 filtering


From: Michael Loftis <mloftis () wgops com>
Date: Wed, 26 Jan 2011 13:24:27 -0700

On Tue, Jan 25, 2011 at 10:49 PM, Mark D. Nagel <mnagel () willingminds com> wrote:

This can bite you in unexpected ways, too.  For example, on a Cisco ASA,
if you add a system-level 'icmpv6 permit' line and if this does not
include ND, then you break ND responses to the ASA.  This is much unlike
ARP, which is unaffected by 'icmp permit' statements for IPv4.  And, the
default with no such lines is to permit all ICMP/ICMPv6 to the ASA. This
seems so obvious in retrospect, but at the time was a bit of a
head-scratcher.


ARP is a seperate protocol supporting IPv4 ... For IPv6 ND is done
using ICMPv6 messages.  A bit confusing transitioning from IPv4/ARP
for sure.

Mark


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