Hi,
I agree with your comment and the proposed change.
Using RFC9602 range should be the preferred way to go. 
Cheers
Bala'zs

-----Original Message-----
From: Tom Hill <t...@ninjabadger.net> 
Sent: Tuesday, August 26, 2025 4:54 PM
To: spring@ietf.org
Subject: [spring] Address ranges, re: draft-ietf-spring-srv6-security-05

[Ritkán kap e-maileket t...@ninjabadger.net. Miért fontos ez a 
https://aka.ms/LearnAboutSenderIdentification ]

Hello,

I realised this has been raised before and I'd been asked to write to the list, 
but I would appreciate some discussion on this point.

In Section 7.1.3, Address Range Filtering, there is a list of example 
infrastructure address ranges to be used for SRv6 SIDs.

--

Some examples of an infrastructure address range for SIDs are:

   1.  ULA addresses
   2.  The prefix defined in [RFC9602]
   3.  GUA addresses

--

I have questions over the format, first and foremost; is this meant to be an 
ordered list? Previous feedback was no, but this format has persisted into the 
latest revision.

If it isn't intended to be ordered, then it must be unordered to prevent the 
same ambiguity.

If it is intended to be ordered, I am concerned with ULA being preferred over 
the purposely defined prefix in RFC9602. I do not feel that recommending ULA is 
preferable to the use of a prefix defined specifically for this use, which we 
now have (thank you Suresh).

--

Regardless of ordering, it is also very concerning that we include GUA 
addressing in the list. I realise these are examples of what might be done 
today, and that it might be "valid" for an operator to do (I would disagree 
vehemently) but when discussing Security Considerations I believe that we have 
a duty to represent such prefix ranges as something other than equals -- they 
are not equal in respect of their use.

Replacing the text above, a suggestion for S7.1.3 might be as follows:

"Implementations of SRv6 should number SIDs within their trusted domain from 
the reserved prefix as defined within RFC9602."

The prefix defined in RFC9602 is explicitly required to be filtered from the 
Internet, and it is far less complex to filter when an organisation is also 
utilising ULA or GUA in other networks adjacent to that of their
SRv6 domain. RFC9602 should be considered as 'the' prefix range to utilise for 
these networks.

--
Tom

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