Infinite loops in client processes --

[Paul Townsend]

On Thu, 27 Jul 2006 09:31:47 -0400, David Blacka wrote:
>Paul Townsend wrote:
>> -----
>> Second try.  I wasn't registered the first time.  I apologize if it's a
>> duplicate.
>> 
>> Recently, I've encountered a number of infinite referral loops (ranges supplied 
>> below).  I use both rwhois-client-1.6.1 and a modified version of jwhois that 
>> understands a basic set of the rwhois syntax.  I've modified the jwhois variant 
>> to the point where it can detect the loop and display a message about it.
>> 
>> RFC2167 describes this condition (Section 3.3.7) as a "recursive referral" and 
>> suggests that a "-notify recurref ..." directive be sent back the the server
> 
>> when the loop is encountered.  My question is to which of the servers should
> 
>> the directive be sent?    Below are the query paths that the modified jwhois
> 
>> followed where it detected a loop.  Note that the start of the "rwhois" portion
>> of the loop depended on how the request was phrased.
>
>Wow, I had totally forgotten about the -notify directive.  In practice,
>the -notify directive is useless.  In rwhoisd, all it does is log
>something, and I seriously doubt any operators look at the log.

Grumble.  Maybe, if a sufficient number of client programs that
encountered this problem sent a "-notify ...", the filesystem containing
the log would fill and the operators would have to look at it to see
what was wrong (nasty grin).

>Basically, it is just important for the client to to handle the referral
>loop.

FWIW - rwhois-client-1.6.1 does not - it keeps following the referrals
until it's interrupted.

>You are right, though.  It is totally unclear to which server the
>-notify directive should be sent.  Looking at your examples, the problem
>is actually rwhois.covad.net.

I agree - rwhois.covad.net	in the 74.0.0.0/15 loop
	  rwhois.insightns.com	in the 74.128.0.0/12 loop
	  rwhois.allstream.com	in the 207.245.0.0/18 loop

All three servers have a punt(?) referral to root.rwhois.net which has
a punt(?) referral to rwhois.arin.net which has a link(?) referral to
the starting server which ....  Perhaps a note should be added to all
rwhois server setup/maintenance documentation that a referral following
client should be used to verify that each piece actually works.

Sigh, I guess it's email time to some tech people.

--    Paul Townsend