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

[Brian E Carpenter <[e-mail]>]

Andrew,

On 22-May-23 23:28, Andrew Campling wrote:
> On 21-May-23 10:29 PM, Brian E Carpenter wrote:
> 
>> And there's the problem. The operator of a large network cannot possibly
>> know which extension headers every host on the network needs. It's called
>> permissionless innovation, and is supposed to be one of the main success
>> factors for the Internet.
> 
> I think the problem with this approach, which I'm interpreting as "allow everything", is that people responsible for the security of public, and especially private, networks need to consider whether any such innovations might introduce new vulnerabilities.  Remember that, for example, CISOs looking after the security of some enterprises may fall foul of regulatory obligations if they cannot show that their networks are as secure as is practical.

Sure. So it's our job to document the best way to secure networks...
  
> More generally, anyone operating zero trust principles would surely only allow those features that they deem necessary, selected extension headers in this case.  This would seem consistent with the point that Fernando made earlier in the thread.

That depends where you choose to apply the zero trust model. As Steve Bellovin argued many years ago in his distributed firewalls paper, distributing the trust model to the end systems is best, because you no longer have to trust any intermediate systems.

https://www.cs.columbia.edu/~smb/papers/distfw.pdf

   Brian