Do you have a question? Post it now! No Registration Necessary. Now with pictures!
- Posted on
- .arpa IP?
August 23, 2006, 12:23 am
rate this thread
I recently connected to a wireless network and it gave this IP:
Could anyone explain me how is this possible? As far as I know a .arpa TLD
does not exist, I have been surfing the internet for years and this is the
I see a .arpa domain
I have a basic idea of what the ARPA network was, the internet foundation
or something like that,
but it does not exist anymore which makes all this even more confusing (??)
Re: .arpa IP? extra information
Not _quite_ enough information.
That doesn't mean it doesn't exist. In fact, it goes back to the 1980s
when DNS was introduced, and is in _constant_ use - you just don't use
that information. Other people do.
BRIEFLY: The Internet works on IP addresses, not names. Humans find it
easier to work with names. As of the middle of this month, there are
approximately 2352 _million_ IP addresses in use. No one server can keep
track of all of that. Likewise there are about 74400 different primary
networks out there (probably several tens of millions of domains).
When you want to have your browser connect to www.example.com, an
application in your computer's operating system asks a name server what
the IP address is for that name. The name server may or may not know, BUT
it knows how to ask one of 13 "root servers". The root servers don't know
either, but they tell the name server to ask the server that knows .com.
That server, knows that the servers that know about "example.com" are
"ns1.example.com", and "ns2.example.com" at address 192.0.2.18 and
192.0.2.35 - go ask them. So the name server _then_ asks ns1.example.com
"what's the address of www.example.com" and gets told the "right" answer
which it then tells your computer. This is called a distributed database.
NOW, how do you find the hostname of 192.0.2.98? Who do you ask? Same
answer - the computer asks the name server, but to avoid confusion, it
gives the address as 184.108.40.206.in-addr.arpa. Notice how when you were
looking at hostnames, the (what do you want to call it - family name) is
at the right side. ".com" Below that, is "example.com". Below that is
"www.example.com". The in-addr.arpa domain is set up the same way,
with the "family" name on the right ".in-addr.arpa", then "192.in-addr.arpa",
then "0.192.in-addr.arpa", and so on. The name server would ask the root
server, be referred to the "in-addr.arpa" server, which would then refer it
to the "192.in-addr.arpa" server and so on. This _seems_ as if it would
be slow, but the name servers remember the intermediate steps - so that
next time someone asks for "ftp.example.com" - it knows to ask the two
"example.com" servers directly without wasting the intermediate steps.
ARPA is now DARPA - and yes it exists. But the name of the domain wasn't
changed just to prevent the hassle. Ask your wife or mother how much crap
she went through when her name changed when she got married. TONS of new
IP address 220.127.116.11 - and the id10t who is running the name server
doesn't feel it required to have it configured properly. 18.104.22.168 to
22.214.171.124 is assigned to the "European Regional Registry", or "RIPE".
According to RIPE, 126.96.36.199 - 188.8.131.52 belongs to "Andrews & Arnold
Ltd" in Bracknell, Berks. in the UK, and the actual address is sub-assigned
to "The Religious Society of Friends" London office.
Re: .arpa IP? extra information
Ok thank you for the explanation Old guy, I get an idea, but still do not
understand how do I get a .arpa domain for myself? I know I can buy a
.com, .net and so on, I just have never seen registrar selling .arpa
Or how I can get my home router to show a .arpa address thats something
I would like to do, I like the domain name.
Whats wrong with the configuration?
Re: .arpa IP? extra information
On 23 Aug 200600, in the Usenet newsgroup alt.computer.security, in article
You don't. They are an administrative domain - the sole purpose is to
use it to translate an IP address to a host address. Look at the example
again - how would the name server know to ask the right server out on the
Internet which host address goes to that IP? Are you going to have it
ask each of the tens of millions of domain DNS servers? How do you even
know the address of those servers? That's the purpose of the in-addr.arpa
You'd have to have an authoritative name server designated by a registrar
so that people would know to ask your system - and then have it
mis-configured to return the bogus name. ICANN, which owns that domain is
not handing it out for registrations. You may want to look at
http://www.icann.org/registrars/accredited-list.html - and you'll notice
that the in-addr.arpa is not available.
The answer is wrong. The hostname of the computer using 184.108.40.206 is
something entirely different - I have no idea what it might actually be,
although it is _possible_ that the domain portion of the name might be
quaker.org.uk. Instead, this id10t has it set to reply into an endless
loop. My system asks "what is the name of 220.127.116.11.in-addr.arpa", and
the answer comes back "18.104.22.168.in-addr.arpa" which is false. Many
mail servers will automatically drop a connection when they get such an
answer. Paranoid firewalls may do likewise. The address doesn't appear
to be currently listed on blocklists I have access to, but I wonder
how long that will continue.
For further reading, see the following RFCs available on the web:
1034 Domain names - concepts and facilities. P.V. Mockapetris.
November 1987. (Format: TXT=129180 bytes) (Obsoletes RFC0973,
RFC0882, RFC0883) (Updated by RFC1101, RFC1183, RFC1348, RFC1876,
RFC1982, RFC2065, RFC2181, RFC2308, RFC2535, RFC4033, RFC4034,
RFC4035, RFC4343, RFC4035, RFC4592) (Also STD0013) (Status: STANDARD)
1035 Domain names - implementation and specification. P.V.
Mockapetris. November 1987. (Format: TXT=125626 bytes) (Obsoletes
RFC0973, RFC0882, RFC0883) (Updated by RFC1101, RFC1183, RFC1348,
RFC1876, RFC1982, RFC1995, RFC1996, RFC2065, RFC2136, RFC2181,
RFC2137, RFC2308, RFC2535, RFC2845, RFC3425, RFC3658, RFC4033,
RFC4034, RFC4035, RFC4343, RFC2137, RFC2845, RFC3425, RFC3658,
RFC4035, RFC4033) (Also STD0013) (Status: STANDARD)
1536 Common DNS Implementation Errors and Suggested Fixes. A. Kumar,
J. Postel, C. Neuman, P. Danzig, S. Miller. October 1993. (Format:
TXT=25476 bytes) (Status: INFORMATIONAL)
1912 Common DNS Operational and Configuration Errors. D. Barr.
February 1996. (Format: TXT=38252 bytes) (Obsoletes RFC1537) (Status:
As you can see, the documentation is quite extensive - heck, there are
even several well known (in the business) books on the subject, such as
"DNS & BIND" 4th edition, ISBN 0-596-00158-4 (622 pgs) which is probably
the best known of the bunch.