Re: Q: inet operators for IPv4 encapsulated in IPv6

[Albrecht Dreß]

Am 06.09.23 19:41 schrieb(en) Erik Wienhold:

The docs don't spell it out, but inet operators and functions expect values of 
the same inet family.  Comparing IPv4 and IPv6 always returns false, e.g. [1].
The only hint in the docs that may imply this is [2]:

        "When sorting inet or cidr data types, IPv4 addresses will always sort
         before IPv6 addresses, including IPv4 addresses encapsulated or mapped
         to IPv6 addresses, such as ::10.2.3.4 or ::ffff:10.4.3.2."

Ah, I missed that section in the docs.  Thanks a lot for your explanation and 
the pointers!

You can write your own function that converts IPv4-mapped IPv6 addresses to 
IPv4 and then do the comparison:

        postgres=# SELECT ltrim(host('::ffff:192.168.1.5'::inet & 
'::255.255.255.255'::inet), ':')::inet;
            ltrim
        -------------
         192.168.1.5
        (1 row)

That's a nice approach, will do that.

Thanks again, Albrecht.

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