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Re: Internet Worm


From: jim () Tadpole COM (jim () Tadpole COM)
Date: Tue, 18 Oct 1994 16:57:11 -0500


I think you will find that Sun put a double lookup into
gethostbyaddr(), to prevent spoofing. This of course goes against
the Unix spirit of 'do one thing only, but do it well'. This double
lookup can be enabled with the resolv+ library by using the
'nospoof' command in its configuration file.

I think that you will find that you are wrong, and the reverse lookup
actually happens in ypserv, specificly in the part that looks up
addresses via the DNS, not the routine in libc.  If you still think
I'm wrong, I invite you to disassemble gethostent.o from libc.a and
take a look for anything that might be code that does a reverse lookup.

The comments about 'nospoof' and resolv+ are accurate.

Jim



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