Default Reverse Lookup name for unused IP in unbound

Unbound
1

If I query reverse look via any public dns for my ISP’s different Ip address, I get this result,

For every IP on which my ISP have made custom record I get this result:

** nslookup 111.111.111.158

nslookup 111.111.111.159.myisp.com

Name: company1.isp.com

** nslookup 111.111.111.159
nslookup 111.111.111.159.myisp.com
Name: company2.isp.com

For several other hundreds IP addresses of my ISP, I get this result as default

** nslookup 111.111.111.160
Name: 111-111-111-160.myisp.com
Address: 111.111.111.160

** nslookup 111.111.111.161
Name: 111-111-111-161.myisp.com
Address: 111.111.111.161

How this is done that every unused ip, no ping replies from them and each ip is showing isp name by default? Do ISP creates manual records for there unused IP’s as well or is there any geenral statemetn defined in there dns?
How I can do this in my Unbound config so that if I do Nslookup for any unused Ip of my LAN it should return like x-x-x-x-mydomain.com ?

2

If I query reverse look via any public dns for my ISP's different Ip address, I get this result,

For every IP on which my ISP have made custom record I get this result:
** nslookup 111.111.111.158
nslookup 111.111.111.159.myisp.com
Name: company1.isp.com
** nslookup 111.111.111.159
nslookup 111.111.111.159.myisp.com
Name: company2.isp.com

For several other hundreds IP addresses of my ISP, I get this result as default

** nslookup 111.111.111.160
Name: 111-111-111-160.myisp.com
Address: 111.111.111.160

** nslookup 111.111.111.161
Name: 111-111-111-161.myisp.com
Address: 111.111.111.161

How this is done that every unused ip, no ping replies from them and each ip is showing isp name by default? Do ISP creates manual records for there unused IP's as well or is there any geenral statemetn defined in there dns?
How I can do this in my Unbound config so that if I do Nslookup for any unused Ip of my LAN it should return like x-x-x-x-mydomain.com ?

The easy way is by installing a wildcard in the reverse zone:

*.e.1.0.8.4.0.0.0.8.9.2.0.1.0.a.2.ip6.arpa. 3600 IN PTR unpop-node.besserwisser.org.

Giving:

$ dig -x 2a01:298:4:801e::0de

; <<>> DiG 9.18.6 <<>> -x 2a01:298:4:801e::0de
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 61153
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
; COOKIE: 5ca933867037179b69ac210f632d8dbd1308320f4deed845 (good)
;; QUESTION SECTION:
;e.d.0.0.0.0.0.0.0.0.0.0.0.0.0.0.e.1.0.8.4.0.0.0.8.9.2.0.1.0.a.2.ip6.arpa. IN PTR

;; ANSWER SECTION:
e.d.0.0.0.0.0.0.0.0.0.0.0.0.0.0.e.1.0.8.4.0.0.0.8.9.2.0.1.0.a.2.ip6.arpa. 3514 IN PTR unpop-node.besserwisser.org.

Reverse DNS of course is like any other DNS, valid strings are valid strings:

; <<>> DiG 9.18.6 <<>> blatant.config.ignorance.e.1.0.8.4.0.0.0.8.9.2.0.1.0.a.2.ip6.arpa. PTR
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 16174
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
; COOKIE: 6f371eae447b44183d532a08632d8e0ec4f9de577cc0854f (good)
;; QUESTION SECTION:
;blatant.config.ignorance.e.1.0.8.4.0.0.0.8.9.2.0.1.0.a.2.ip6.arpa. IN PTR

;; ANSWER SECTION:
blatant.config.ignorance.e.1.0.8.4.0.0.0.8.9.2.0.1.0.a.2.ip6.arpa. 3600 IN PTR unpop-node.besserwisser.org.

If you want to have a more special RDATA section in the reply, an
active authoritative server is required, where ansvers are synthesized
on-the-fly.

3

Ok with wildcard tip, I proceed little further.
I added following record in reverse zone

Now If I do nslookup for any LAN IP (pool 192.168.1.x/24) who doesn’t have any PTR record, it resolves to

192.168.1.200
Name: example.com

Address: 192.168.1.200

How can I turn this example.com to default as IP.example.com (e.g: 192-168-1-200.example.com)

4

Ok with wildcard tip, I proceed little further.

I added following record in reverse zone

Now If I do nslookup for any LAN IP (pool 192.168.1.x/24) who doesn’t have any PTR record, it resolves to

192.168.1.200
Name: example.com

Address: 192.168.1.200

How can I turn this example.com to default as IP.example.com (e.g: 192-168-1-200.example.com)

You can either replace the wildcard record in the 1.168.192.in-addr.arpa zone with lots of individual PTR records (this is more practical with IPv4 than IPv6) or you can…

… do something like that.

Joe

5

Ok with wildcard tip, I proceed little further.
I added following record in reverse zone

* IN PTR example.com.

Now If I do nslookup for any LAN IP (pool 192.168.1.x/24) who doesn't have any PTR record, it resolves to

> 192.168.1.200
Name: example.com
Address: 192.168.1.200

How can I turn this example.com to default as IP.example.com (e.g: 192-168-1-200.example.com)

As I wrote a bit further down in my previous reply:

If you want to have a more special RDATA section in the reply, an
active authoritative server is required, where ansvers are synthesized
on-the-fly.

I'm afraid this is a bit off-topic here, as it deals with serving data
and not with looking it up, and unbound is definitely aimed at looking
up.

Several database- or script-driven backends have been developed for
various authoritative name servers, and while I've never tried myself,
I'm certain you'll find one that does what you want.

6

Thank you for your detailed response. Surely its my lack of knowledge, Let me try playing with different options & will share results.

7

I forgot to update the thread. I managed to sort this by using BIND & following statement in Reverse Zone File & getting desired results.

$GENERATE 1-255 $ IN PTR 10-11-11-$.example.com.