29 May
2015
29 May
'15
4:49 p.m.
On 5/29/15 12:42 PM, Pedja YT9TP wrote:
I am not quite clear what you mean as subdomain.
Can you point out of some sample of domain usage which is not subdomain?
Pedja
YT9TP
Here is a non-subdomained address:
*aa6hf.ampr.org*
Name: aa6hf.ampr.org
Address: 44.17.0.128
aa6hf.ampr.org mail exchanger = 10 aa6hf.ampr.org.
aa6hf.ampr.org mail exchanger = 20 linux.aa6hf.ampr.org.
Authoritative answers can be found from:
*ampr.org nameserver = hamradio.ucsd.edu.*
ampr.org nameserver = munnari.OZ.AU.
ampr.org nameserver = ns1.defaultroute.net.
ampr.org nameserver = ns0.comgw.net.
ampr.org nameserver = ns2.threshinc.com.
ampr.org nameserver = ampr.org.
ampr.org nameserver = ampr-dns.in-berlin.de.
ampr.org internet address = 44.0.0.1
It is not a subdomain, it's address is
served by the ampr.org nameservers.
Here is a delegated subdomain (some lines removed for more clarity and
less clutter):
*de.ampr.org*
de.ampr.org text = "de.ampr.org - Seit 2012-03-17 im Testbetrieb.
hamradio.ucsd.edu *delegated*"
de.ampr.org mail exchanger = 20 kle.nw.schule.de.
de.ampr.org
origin = de.ampr.org
mail addr = ipkoord.de.ampr.org
Name: de.ampr.org
Address: 134.91.19.148
*de.ampr.org nameserver = db0res.ampr.org.*
de.ampr.org nameserver = db0fhn.efi.fh-nuernberg.de.
de.ampr.org nameserver = ns.db0fhn.ampr.org.
de.ampr.org nameserver = db0res.de.
It is a subdomain because it is being served
by de.ampr.org name
servers, not ampr.org. No x.de.ampr.org addresses are served by
ampr.org. This can be further subdomained, as many times as needed.
Subdomaining hands off (delegates) the responsibility for a namespace
(e.g., de.amp.org) or a range of IP addresses (e.g., 44.130/16, meaning
44.130.0.0 through 44.130.255.255) to another entity and nameserver(s).
The advantage of a delegated subdomain is that you can update your
subdomain's DNS records without having to get someone else to do it.
The disadvantage is that someone must install, maintain, and operate a
DNS server. I do this for my own (non-ham) domains, but I've had decades
of experience with DNS servers (I have been working with the Internet
since before DNS was created, ALL of the hosts that were public were
listed in a single file and installed on every host! :-), not everyone
wants to go to that effort.
I'm just getting back into Packet Radio and the 44 net after a decade
and a half dedicated to work and family, and I'm still learning how
things have been put together in the intervening years.
- Richard, VE7CVS