IPv6 ingress filtering

[Brian E Carpenter]

On 15-May-19 04:22, Amos Rosenboim wrote:
> Let me just clarify few points:
> The suggested filter is not for the protocol, but for the 2002::/16 address space.

Sure. But this is quite complicated; more complicated than I imagined when we invented 6to4. I really suggest reading https://tools.ietf.org/html/rfc6343 and then https://tools.ietf.org/html/rfc7526 carefully, for those that haven't done so.

According to Google statistics, 6to4 has been immeasurably small for at least a year (0.00%), but I don't see why it would do you any harm.
 
> Also the traffic I am seeing is between addresses  within this prefix to addresses of our native IPv6 users.

That's exactly what you should see, IMHO. What % of total IPv6 traffic is that, as a matter of curiosity?
 
> As for policy - we tend to be as permissive as we can, and we certainly wouldn’t like to restrict what is left from p2p apps.

No argument from me.

   Brian

> 
> Amos
> 
> Sent from my iPhone
> 
> On 14 May 2019, at 18:50, JORDI PALET MARTINEZ <jordi.palet at consulintel.es <mailto:jordi.palet at consulintel.es>> wrote:
> 
>> Hi Marc,
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>>  
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>> I don’t agree. There are many users with tunnel brokers that use 6in4. If you filter 6to4 as a protocol, you’re also filtering all those users’ traffic.
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>> Not everybody is lucky enough to have native IPv6 support from its ISP.
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>>
>> Saludos,
>>
>> Jordi
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>>  
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>> El 14/5/19 17:46, "Marc Blanchet" <ipv6-ops-bounces+jordi.palet=consulintel.es at lists.cluenet.de <mailto:ipv6-ops-bounces+jordi.palet=consulintel.es at lists.cluenet.de> en nombre de marc.blanchet at viagenie.ca <mailto:marc.blanchet at viagenie.ca>> escribió:
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>>  
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>> 6to4 has been a good transition technology to help deploy IPv6 in the early days. However, it has intrinsically bad latency issues as its routing is based on the underlying IPv4, which can be pretty bad for non 6to4 destinations (e.g. normal IPv6 addresses). Moreover, its IPv6 in IPv4 tunnelling technology is likely to be filtered by various intermediate devices in the path. My take is that we shall declare 6to4 over and dead, thank you very much for your service. So I would suggest to filter it. If not, users may get latency issues that will go into support calls unncessarily.
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>> Marc.
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>> On 14 May 2019, at 11:24, Amos Rosenboim wrote:
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>>     Hello,
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>>      
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>>     As we are trying to tighten the security for IPv6 traffic in our network, I was looking for a reference IPv6 ingress filter.
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>>     I came up with Job Snijders suggestion (thank you Job) that can be conveniently found at whois -h whois.ripe.net <http://whois.ripe.net> fltr-martian-v6
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>>      
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>>     After applying the filter I noticed some traffic from 6to4 addresses (2002::/16) to our native IPv6 prefixes (residential users in this case).
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>>     The traffic is a mix of both UDP and TCP but all on high port numbers on both destination and source.
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>>     It seems to me like some P2P traffic, but I really can’t tell.
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>>     This got me thinking, why should we filter these addresses at all ?
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>>     I know 6to4 is mostly dead, but is it inherently bad ?
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>>     And if so, why is the prefix (2002::/16) still being routed ?
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>>     Thanks,
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>>      
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>>     Amos Rosenboim
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>>     -- 
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>>      
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>>
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