[Netdot-users] ip6.arpa PTR records

Discussion:

Matt Zagrabelny

2017-01-03 22:28:44 UTC

Greetings!

Is anyone using the reverse zone for v6 address blocks successfully?

I've added an ip6.arpa zone to a v6 address block, but I am not
getting PTR records created.

I've had issues before (for in-addr.arpa IPv4) with creating the
(reverse) zone in the DNS Zones vs IP Block Zones. So, I tried
creating the zone both via the "DNS Zones" -> new and also under the
"IP Block" -> Zones -> Reverse Zones -> add, but still can't get v6
PTR records to be auto-created.

Thanks!

-m

Carlos Vicente

2017-01-04 14:52:25 UTC

Permalink

Hi Matt,

It definitely works because I've been using the feature for years. The
procedure you mention:

"IP Block" -> Zones -> Reverse Zones -> add

is the recommended one because Netdot will generate the right zone label
for you based on the block.

PTR records should be created/updated automatically each time you
add/update a AAAA record.

cv

Post by Matt Zagrabelny
Greetings!
Is anyone using the reverse zone for v6 address blocks successfully?
I've added an ip6.arpa zone to a v6 address block, but I am not
getting PTR records created.
I've had issues before (for in-addr.arpa IPv4) with creating the
(reverse) zone in the DNS Zones vs IP Block Zones. So, I tried
creating the zone both via the "DNS Zones" -> new and also under the
"IP Block" -> Zones -> Reverse Zones -> add, but still can't get v6
PTR records to be auto-created.
Thanks!
-m
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Matt Zagrabelny

2017-01-04 15:41:37 UTC

Permalink

Hey Carlos,

A few questions for you, if you don't mind. :)

1. Is there a configuration option for auto creating PTR records? Or
if an Address Space (IP Block) has a Reverse DNS Zone then PTR records
get created automatically?

2. When you add a Reverse DNS Zone to an Address Space, does it
iterate through all the children and check for A/AAAA records and
create PTR records? Or does it just create PTR records for new A/AAAA
records within the Address Space?
2a. If the PTRs for A/AAAA get generated when a Reverse Zone is added
to an Address Space, where in the code do the PTRs get added?

3. Are the results of creating a new ip6.arpa zone via:

"DNS Zones" -> new
and then adding the new zone to the Address Space's Reverse DNS Zones

and

"Address Space" -> Zones -> Reverse DNS Zones -> add

the same? That is, is there any functional difference between the two?

4. Can you give an example of when to use the Template Zone when
creating a new zone?

Like I said, I've had some mixed results with the in-addr.arpa PTR
records for a v4 Address Space. I'd love to get the definitive word on
reverse zones so that I know how the systems is supposed to be
behaving.

FWIW, we're using Pg 9.4.9.

Thanks!

-m

Post by Carlos Vicente
Hi Matt,
It definitely works because I've been using the feature for years. The
"IP Block" -> Zones -> Reverse Zones -> add
is the recommended one because Netdot will generate the right zone label for
you based on the block.
PTR records should be created/updated automatically each time you add/update
a AAAA record.
cv

Matt Zagrabelny

2017-01-04 17:00:34 UTC

Permalink

Found some answers from the code...

Post by Matt Zagrabelny
2. When you add a Reverse DNS Zone to an Address Space, does it
iterate through all the children and check for A/AAAA records and
create PTR records? Or does it just create PTR records for new A/AAAA
records within the Address Space?
From the answer to 2a it looks like it should add all missing PTR

records when the zone is created.

Post by Matt Zagrabelny
2a. If the PTRs for A/AAAA get generated when a Reverse Zone is added
to an Address Space, where in the code do the PTRs get added?

In lib/Netdot/Model/Zone.pm

sub insert

# Create PTR records if necessary
$newzone->is_dot_arpa() && $newzone->add_ptrs();

-m

Matt Zagrabelny

2017-01-04 22:46:06 UTC

Permalink

Hey Carlos,

We are being bit by:

https://osl.uoregon.edu/redmine/issues/1909

I've coded up the fix for the above, but we are still hitting an issue
somewhere. I'll keep digging.

Thanks!

-m

Matt Zagrabelny

2017-01-05 03:06:13 UTC

Permalink

Post by Matt Zagrabelny
Hey Carlos,

https://osl.uoregon.edu/redmine/issues/1909
I've coded up the fix for the above, but we are still hitting an issue
somewhere. I'll keep digging.

Looks like there is some amount of case sensitiveness with v6 things
in Netdot. If I put a well placed lc() in the code I can get the PTR
records generated.

Our prefix was entered lowercase:

2607:ea00:200::/40

and the reverse zone was correctly calculated as:
2.0.0.0.a.e.7.0.6.2.ip6.arpa, but when Netdot looked for descendants
of our prefix and calculated their reverse names it used uppercase:

5.3.0.0.0.0.0.0.0.0.0.0.0.0.0.0.9.0.1.0.0.0.2.0.0.0.A.E.7.0.6.2.ip6.arpa

and the zone search fails for the uppercase version of the reverse
name - which is interesting because DNS is case insensitive.

Thus the lc hack helped illustrate the case sensitiveness - at least
for v6 reverse zone stuff.

-m