Re: [v6ops] [IPv6] [OPSEC] Why folks are blocking IPv6 extension headers? (Episode 1000 and counting) (Linux DoS)

[Fernando Gont <[e-mail]>]

Hi, Ole,

On 22/5/23 15:36, Ole Troan wrote:
[...]>>
>> As a host and networking stack developer, I view the network and these
>> arbitrary inconsistent security policies as the problem not as the
>> solution to application and host security. The best tool developers
>> have is to encrypt as much of the packet as possible to keep network
>> providers from meddling in protocol layers they shouldn't be, but
>> unfortunately that isn't applicable to all protocols like EH for
>> instance (although, given that IPsec was on Fernando's approved list
>> of extension headers, I suppose we could hide all the extension
>> headers we want in IPsec :-) )
> 
> I don’t think Fernando has argued the case that some EHs should be filtered in public transit networks?

No, I certainly wasn't. -- I was just arguing about filtering at e.g. an 
Enterprise edge.

As for transit networks... it's tricky. In a lof of cases, the dropping 
of such packets doesn't have to do with trying to protect the 
destination AS, but rather because EHs may result in e.g. performance 
issues when the transit AS tries to protect e.g. their own 
infrastructure (see RFC9098). In such scenarios, I'm not sure there are 
many alternatives to just dropping the offending packets (even if 
undesirable).


> In the whole I think it’s not a good idea that the IETF has some working groups working hard at defining new protocols and other working groups working hard at defining policies to block them.

FWIW, I don't think anyone wants to block them, but rather to provide 
guidance about what's sensible to do. e.g., what to do with EHs at the 
Enterprise trust boundary is a usual question from Enterprise folks.



> Now for EHs in general. Their functionality of providing a separate signalling channel independent of the application… it might be time that we accept that this was a bad idea. Which deployment status has confirmed.

Agreed on this.

Cheers,
-- 
Fernando Gont
SI6 Networks
e-mail: [e-mail]
PGP Fingerprint: F242 FF0E A804 AF81 EB10 2F07 7CA1 321D 663B B494