A records, PTR records, and TTL setting

[Havard Eidnes]

Hi,

first let me slide out on a tangent, and then say a few words
about what I think this is about:

>> Suppose you have a shoe. You can call it "a shoe" or "the shoe".
>> Suppose you have two shoes, because you have two feet. Are they identical?
>
> I'd like to change the analogy - to a person with two ears.  And one head. 
> 
> The head (brain?, CPU?) knows it is referred to as "deb12dell"
> because that is what I named her.

Careful with the terminology here :), this reminds me of this
entry from the "fortune" program:

	   "... The name of the song is called 'Haddocks' Eyes'!"
	   "Oh, that's the name of the song, is it?" Alice said, trying to
   feel interested.
	   "No, you don't understand," the Knight said, looking a little
   vexed.  "That's what the name is called.  The name really is, 'The Aged
   Aged Man.'"
	   "Then I ought to have said "That's what the song is called'?"
   Alice corrected herself.
	   "No, you oughtn't:  that's quite another thing!  The song is
   called 'Ways and Means':  but that's only what it is called you know!"
	   "Well, what is the song then?" said Alice, who was by this time
   completely bewildered.
	   "I was coming to that," the Knight said.  "The song really is
   "A-sitting on a Gate":  and the tune's my own invention."
		   -- Lewis Carroll, "Through the Looking Glass"

> She is standing in the doorway to two rooms, The left ear
> listens to zone Living Room (ethernet).  The right ear listens
> to zone Reading Room (wi-fi).
>
> If someone in the Living Room (ethernet) asks where is she
> ("deb12dell") located, I expect the answer to be she is at
> "192.168.60.175".

You can name more or less whatever you like in the DNS.  You can
name hosts, be they single-homed or multi-homed, or if you have a
need to identify a particular interface on a multi-homed host,
you can name the interface on the host with a distinct name.
It's all up to you, dictated by your needs and what turns out to
be convenient or even necessary.

With that said, multi-homed hosts are IMHO somewhat of a kludge
-- you don't need to change expectations much before they end up
as routers.  There's also the matter of whether a multi-homed
host implements the "strong" or "weak" host model.  Ref.
https://en.wikipedia.org/wiki/Host_model -- that may influence
whether you want or need to name the individual interfaces.

Best regards,

- Håvard