NAT66 was Re: using "reserved" IPv6 space

Seth Mos seth.mos at
Tue Jul 17 05:47:30 UTC 2012

Op 17 jul 2012, om 04:56 heeft Grant Ridder het volgende geschreven:

> If you are running an HA pair, why would you care which box it went back
> through?

Because it could be/is a stateful firewall and the backup will drop the traffic. (FreeBSD CARP)



> -Grant
> On Monday, July 16, 2012, Mark Andrews wrote:
>> In message <CAD8GWsswFwnPKTfxt=
>> squUmZofs3_-yriHY8o4Gt3W9+x6fVUQ at <javascript:;>>, Lee
>> writes:
>>> On 7/16/12, Owen DeLong <owen at <javascript:;>> wrote:
>>>> Why would you want NAT66? ICK!!! One of the best benefits of IPv6 is
>> being
>>>> able to eliminate NAT. NAT was a necessary evil for IPv4 address
>>>> conservation. It has no good use in IPv6.
>>> NAT is good for getting the return traffic to the right firewall.  How
>>> else do you deal with multiple firewalls & asymmetric routing?
>> Traffic goes where the routing protocols direct it.  NAT doesn't
>> help this and may actually hinder as the source address cannot be
>> used internally to direct traffic to the correct egress point.
>> Instead you need internal routers that have to try to track traffic
>> flows rather than making simple decisions based on source and
>> destination addresess.
>> Applications that use multiple connections may not always end up
>> with consistent external source addresses.
>>> Yes, it's possible to get traffic back to the right place without NAT.
>>> But is it as easy as just NATing the outbound traffic at the
>>> firewall?
>> It can be and it can be easier to debug without NAT mangling
>> addresses.
>> The only thing helpful NAT66 does is delay the externally visible
>> source address selection until the packet passes the NAT66 box.
>> Mark
>> --
>> Mark Andrews, ISC
>> 1 Seymour St., Dundas Valley, NSW 2117, Australia
>> PHONE: +61 2 9871 4742                 INTERNET: marka at<javascript:;>

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