IPv6 ingress filtering

Tue May 14 17:48:45 CEST 2019

Hi David,

I agree that this is an operator decision, however, you should consider implications of calls in your helpdesk because you’re breaking p2p apps.

I’ve heard many times “6to4” is deprecated, and people not always look at the RFCs to confirm what others tell (which is in this case incorrect), so they got a wrong impression of the real situation.

Regards,

Jordi

El 14/5/19 17:40, "David Farmer" <ipv6-ops-bounces+jordi.palet=consulintel.es at lists.cluenet.de en nombre de farmer at umn.edu> escribió:

While I happen to agree with you 2002::/16 SHOULD NOT be filtered, and RFC 7526 is quite clear that 2002::/16 is still valid. However, it is perfectly permissible to filter it, if that is the policy a network operator wishes to enforce. 

On Tue, May 14, 2019 at 10:30 AM JORDI PALET MARTINEZ <jordi.palet at consulintel.es> wrote:

6to4 is still a valid protocol. IT SHOULD NOT be filtered. 6to4 uses the same protocol as other tunnels such as 6in4 (protocol 41).

https://www.ietf.org/rfc/rfc3056.txt

It works fine for peer to peer applications.

What the IETF deprecated is anycast for 6to4 relays:

https://tools.ietf.org/html/rfc7526

I believe Hurricane Electric still hosts 6to4 relays.

Regards,

Jordi

El 14/5/19 17:25, "Amos Rosenboim" <ipv6-ops-bounces+jordi.palet=consulintel.es at lists.cluenet.de en nombre de amos at oasis-tech.net> escribió:

Hello,

As we are trying to tighten the security for IPv6 traffic in our network, I was looking for a reference IPv6 ingress filter.

I came up with Job Snijders suggestion (thank you Job) that can be conveniently found at whois -h whois.ripe.net fltr-martian-v6

After applying the filter I noticed some traffic from 6to4 addresses (2002::/16) to our native IPv6 prefixes (residential users in this case).

The traffic is a mix of both UDP and TCP but all on high port numbers on both destination and source.

It seems to me like some P2P traffic, but I really can’t tell.

This got me thinking, why should we filter these addresses at all ?

I know 6to4 is mostly dead, but is it inherently bad ?

And if so, why is the prefix (2002::/16) still being routed ?

Thanks,

Amos Rosenboim

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