A records, PTR records, and TTL setting

[Jon Murphy]

Hello!  Newbie here and I am looking for help with A records and PTR records.  I just started learning unbound and came across things that confuse me.  I am experimenting with unbound Version 1.18.0.  My unbound is for a local network.


I have one device that has two network interfaces (ethernet and Wi-Fi).  

I added this Ethernet to unbound:
  deb12dell.localdomain. 60 IN A 192.168.60.175
  175.60.168.192.in-addr.arpa. 60 IN PTR deb12dell.localdomain.

For the 2nd network interface on "deb12dell" I added two more lines.  And yes, all seems fine!
  deb12dell.localdomain. 60 IN A 192.168.65.180
  180.65.168.192.in-addr.arpa. 60 IN PTR deb12dell.localdomain.

then...

I read somewhere that I should only have one A record per device (with multiple interfaces).  Like this:
  deb12dell.localdomain. 60 IN A 192.168.60.175
  175.60.168.192.in-addr.arpa. 60 IN PTR deb12dell.localdomain.
  180.65.168.192.in-addr.arpa. 60 IN PTR deb12dell.localdomain.


And I read somewhere else I should only have one PTR record per device. Like this:
  deb12dell.localdomain. 60 IN A 192.168.65.180
  180.65.168.192.in-addr.arpa. 60 IN PTR deb12dell.localdomain.
  deb12dell.localdomain. 60 IN A 192.168.65.180

And the above two examples just do not "feel" right.

So my question is:
- should there only be one A Record per device?
- or maybe only one PTR Record per device?

I’ve searched Giggle and I looked through the mailing list but did not find an answer.

===

• Concerning TTL
If I send A & PTR records to unbound via `unbound-control local_data` and I do NOT include the TTL value.  Then I list the records via `unbound-control list_local_data` and the new records show up with a default TTL value of 3600.

I tried adding all of these items, separately, to unbound.conf to see if I can set the default TTL but none work.

 server:
   # cache TTL settings
   cache-max-ttl:
   cache-min-ttl:
   cache-max-negative-ttl:
   infra-host-ttl:

How do I set the default TTL for A records and PTR records within unbound.conf??

Best regards,  Jon