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farfatchedyesterday at 11:10 PM2 repliesview on HN

The title of the post suggests the issue is allowing that syntax in URLs.

Is there an equivalent syntax for IPv4 addresses?


Replies

toast0today at 4:39 AM

No, IPv4 doesn't have the concept of addresses that are scoped to a particular interface.

Rfc3927 which standardizes the use of 168.254.0.0/16 for ipv4 link local was published in 2005, mentions scoped addresses but does not offer any solutions.

However, nothing really relies on ipv4 link local addressing, and most networks don't use it. It's a conceptual problem that these are interface scoped addresses and there's no (standard) way to specify them to applications, but it doesn't cause actual problems.

On the other hand, ipv6 neighbor discovery uses ipv6 link local addresses, so they have to work. And you might try to use them for other things... but then you need to pass through the scope. It's kind of ugh when it causes problems.