[HamWAN PSDR] DNS mapping

Dean Gibson AE7Q hamwan at ae7q.com
Thu May 15 21:49:18 PDT 2014


I did:

=>dig -x 44.24.240.173 @a.ns.hamwan.net.

; <<>> DiG 9.2.4 <<>> -x 44.24.240.173 @a.ns.hamwan.net.
; (1 server found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 55622
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;173.240.24.44.in-addr.arpa.    IN      PTR

;; ANSWER SECTION:
*173.240.24.44.in-addr.arpa. 3600 IN     PTR     ae7q.hamwan.net.*

;; Query time: 147 msec
;; SERVER: 44.24.244.2#53(44.24.244.2)
;; WHEN: Thu May 15 20:44:05 2014
;; MSG SIZE  rcvd: 73

=>dig ae7q.hamwan.net. @a.ns.hamwan.net.

; <<>> DiG 9.2.4 <<>> ae7q.hamwan.net. @a.ns.hamwan.net.
; (1 server found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 46180
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;ae7q.hamwan.net.               IN      A

;; AUTHORITY SECTION:
*ae7q.hamwan.net.        3600 IN      NS      ns1.ae7q.ampr.org.*

;; Query time: 101 msec
;; SERVER: 44.24.244.2#53(44.24.244.2)
;; WHEN: Thu May 15 20:45:39 2014
;; MSG SIZE  rcvd: 64

=>dig ns1.ae7q.ampr.org. @ampr.org.

; <<>> DiG 9.2.4 <<>> ns1.ae7q.ampr.org. @ampr.org.
; (1 server found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 27978
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 7, ADDITIONAL: 1

;; QUESTION SECTION:
;ns1.ae7q.ampr.org.             IN      A

;; ANSWER SECTION:
*ns1.ae7q.ampr.org.      3600 IN      A       44.24.240.173*

;; AUTHORITY SECTION:
ampr.org.               3600    IN      NS ampr-dns.in-berlin.de.
ampr.org.               3600    IN      NS      ampr.org.
ampr.org.               3600    IN      NS munnari.OZ.AU.
ampr.org.               3600    IN      NS ns1.defaultroute.net.
ampr.org.               3600    IN      NS ns2.threshinc.com.
ampr.org.               3600    IN      NS ns0.comgw.net.
ampr.org.               3600    IN      NS hamradio.ucsd.edu.

;; ADDITIONAL SECTION:
ampr.org.               3600    IN      A       44.0.0.1

;; Query time: 157 msec
;; SERVER: 44.0.0.1#53(44.0.0.1)
;; WHEN: Thu May 15 20:47:46 2014
;; MSG SIZE  rcvd: 263

Now, this is not correct.  While I appreciate the PTR record for 
44.24.240.173, it needs to point to a *hostname* record ("A" or CNAME"), 
not a *domainname* record.  This is not the fault of the PTR record, but 
the record that it points to:  The NS record for ae7q.hamwan.net 
effectively declares ae7q.hamwan.net as a *subdomain*, with 
ns1.ae7q.ampr.org as its*nameserver*.  Now, ns1.ae7q.ampr.org has the IP 
address of 44.24.240.173, but that doesn't mean that the domain 
ae7q.hamwan.net is anywhere near 44.24.240.x.

The correct solution to this problem is to replace the NS record for 
ae7q.hamwan.net with a reference to a host;  eg:

 1. ae7q.hamwan.net.  3600  IN  A 44.24.240.173
 2. ae7q.hamwan.net.  3600  IN  CNAME ns1.ae7q.ampr.org.

The administrative advantage of the CNAME is that if my IP address 
changes, you don''t have to change the forward record (you'll still have 
to update PTR records).  The administrative disadvantage is that the 
CNAME is dependent upon a different administrative organization.  
However, neither solution above allows for ae7q.hamwan.net to be a 
subdomain.

If you want to allow ae7q.hamwan.net to be a subdomain, you need to lay 
the following foundation:

173.240.24.44.in-addr.arpa.  3600  IN PTR  ns1.ae7q.hamwan.net.  ; (or 
ns1.ae7q.ampr.org.)
ae7q.hamwan.net.             3600  IN  NS ns1.ae7q.hamwan.net.  ; (or 
ns1.ae7q.ampr.org.)
ns1.ae7q.hamwan.net.         3600  IN  A 44.24.240.173         ; (if 
ns1.ae7q.ampr.org. is not used)

That by itself will not allow *me* to add subdomain records, but it lays 
the foundation.  I prefer creating ns1.ae7q.hamwan.net (all three 
records above), as it keeps the records independent of a different 
administrative organization.

If you want to get carried away, you could also add the following record:

www.ae7q.hamwan.net.  3600  IN  CNAME ns1.ae7q.hamwan.net.  ; (or 
ns1.ae7q.ampr.org.)

-- Dean
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