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Re: domain IN-ARPA.ADDR

  • From: bmanning
  • Date: Thu Mar 18 08:11:06 1999

> I was trying to find a way to check whether an IP address is used by some
> host without actually probing it. DNS sounds like a good way to go, but
> I'v heard that domain "IN-ARPA.ADDR" is not well maintained and updated.
> Is that true? If so, how un-dependable it could be?
> Thanks a lot
> Yixin Jin
> UCLA, Computer Science Dept.

	the rumors of poorly maintained in-addr zones are just that.
	the data suggest that the forward tree was better maintained
	in, roughly 1993-1996/7.  Since then there has been higher
	noise injection in the forward tree and the inverse tree has
	more accurate data.  Rough numbers indicate that regardless
	of the database in question (whois, rwhois, DNS forward, DNS inverse,
	any of the iRR databases (ripe, RA, MCI, ANS and some of the newer
	ones like arin and apnic)) the data, as a whole, has about 40%
	inaccurate data. the reasons why are many but can be boiled down to
	at least two points:
		- centralized repositories "distance" people from
		  the resources they have been delegated to manage.
		- there are few operational requirements for maintaining
		  the accuracy of the data.