rlogind/named interaction?
Steven M. Schultz
sms at wlv.imsd.contel.com
Wed Mar 7 08:24:35 AEST 1990
Are the names returned from gethostbyaddr() using the
resolver routines and 'named' supposed to be fully
qualified domain names? If not, why not?
If so, then what is the correct fix to a problem i am currently
seeing in 'rlogind' (4.3BSD, Vax-8650)? The version of
'rlogind' is 5.22.1.7 dated 9/11/89, and the problem is in
the "verification" process 'rlogind' performs to make sure
the remote host is really himself.
'Rlogind' does a gethostbyaddr() to look up the name of the
client host, receives a successfull response, and then
performs a gethostbyname() using the name returned earlier.
Unfortunately, there is not a trailing '.' at the end of
the name returned by gethostbyaddr() and RES_DNSRCH is ON (by
default), so the resolving routines merrily start appending the
various domain subcomponents and issuing queries to the 'named'.
In turn, 'named' ends up wandering out to the root servers before
the domain search path is empty and a query on the ORIGINAL
name is done (query ends up back in the local domain finally), at
which point the 'rlogin' completes. On relatively lightly loaded
8650 a 'rlogin' has taken up to 2 minutes to complete. A debug
run of 'named' showed him going outside himself for local hosts
because of the RES_DNSRCH action.
Is the correct fix to append a '.' to the name returned by
gethostbyaddr()? Or is it preferable to turn off RES_DNSRCH
before performing the gethostbyname()? Or should the resolver
routines check the domain part of a name to see if it already
matches the local domain?
Steven M. Schultz
sms at wlv.imsd.contel.com
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