[OFF-TOPIC] Question about ClouDNS (and others') ALIAS records
Karl Auer
kauer at biplane.com.au
Tue Mar 26 11:49:15 UTC 2024
I'm puzzled by the ClouDNS "ALIAS" record. I was wondering if anyone
knows how it is handled "under the hood"?
It seems to be a non-standard extension that some DNS providers
support. It seems to work similarly to, but not quite the same way as,
a CNAME. Its big advantage over a CNAME is that it can coexist with
other records of the same name (LHS). However, it seems to be non-
standard.
- when you look up the LHS, you do not get the ALIAS RHS back
- it seems to internally look up the RHS, and return those results
- if you make an A query, you get any matching A records back, as well
as the results from any ALIAS records with the same LHS
- the TTLs of records obtained via the ALIAS are inherited from the TTL
of the ALIAS record
- the real TTLS of the A records behind the ALIAS are lost. This seems
to be risky
Same providers say it is faster to resolve than a CNAME; I can't see
why that would be.
Regards, K.
--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Karl Auer (kauer at biplane.com.au, he/him)
http://www.biplane.com.au/kauer
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