[AusNOG] Globally Routed IPv6 and Windows Firewall

Greg Anderson ganderson at raywhite.com
Fri Jul 25 13:34:30 EST 2014


Definitely not a new problem, but I would consider it a previously very
uncommon problem.

Whilst we seem to agree on filtering at the edge - is this something that
is going to be something used in the residential space?  This is very clear
in the enterprise space where things are less dynamic, but at home you are
now potentially opening firewall ports in two places, and Joe Public is not
going to understand how to do these things.


On 25 July 2014 13:20, Damien Gardner Jnr <rendrag at rendrag.net> wrote:

> What I do (and we do at work) is run stateful firewalling on the
> home/office router, and don't allow inbound traffic on v6 unless it's for
> an established session.   Same as we did all those years ago when our
> homes/offices had a public /24 (We all had that at home right? ;) ).   It's
> certainly not a new problem :)
>
> Cheers,
>
> DG
>
>
> On 25 July 2014 13:11, Greg Anderson <ganderson at raywhite.com> wrote:
>
>> Good day Ladies and Gentlemen!
>>
>> I had a quick question because try as I might, anybody I have asked this
>> question to so far (and Google) have been unable to answer the question for
>> me.
>>
>> With the deployment of a dual stack IPv6 solution either in a corporate
>> or residential environment, I expect most users would have a single NIC in
>> most cases.
>>
>> For Windows firewall, IPv4 addresses in common cases are not globally
>> routed addresses that often have less restrictive firewall rules and
>> services running on them (EG SNMP, File/Printer sharing, RDP, Homegroup
>> etc).  In these cases, some would often use "Domain" or "Private" firewall
>> profiles on these NIC's.
>>
>> With the deployments of IPv6, they will also have local link IPv6
>> addresses (fine as they are not globally routed either obviously), and at
>> some point many will have a globally routed IPv6 address.  So this means,
>> for a given NIC, you will now have:
>>
>> - IPv4 Reserved address for Private local networking
>> - IPv6 Reserved address for Private local networking
>> - IPv6 Globally routed address (and possibly a second temporary address)
>>
>> Suddenly when the deployment of Globally routed IPv6 addresses happen:
>> because the NIC has a private profile there is suddenly private services
>> exposed to the Internet.  (Let's put our tin foil hat on and ignore the
>> difficulties of brute force scanning an IPv6 subnet).
>>
>> Option 1 is obvious - change your NIC's network type to public, and if
>> you don't want everything to break reconfigure all your rules to permit
>> traffic only from local link addresses (IE - a real pain in the _)
>>
>> Is there an option 2?  Ideally, I would like the public ranges to be
>> automatically detected (or specifically reconfigurable) as a globally
>> routed IP address range and therefore to be able to apply multiple profiles
>> (Public and Private/Domain) to a single NIC.
>>
>> I am considering this from a residential dumb end user perspective as
>> well as enterprise - so whilst I would like a technical solution (and I am
>> aware those of us smart enough can still firewall at the edge just like we
>> do today) - many residential users will not have these skills - they are
>> likely to really open themselves up.  So I am interested to see if I am
>> missing something very obvious...
>>
>> Thoughts?
>>
>> - Greg
>>
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>>
>>
>
>
> --
>
> Damien Gardner Jnr
> VK2TDG. Dip EE. GradIEAust
> rendrag at rendrag.net -  http://www.rendrag.net/
> --
> We rode on the winds of the rising storm,
>  We ran to the sounds of thunder.
> We danced among the lightning bolts,
>  and tore the world asunder
>



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