Resolver Issues (non valid hostname characters)

Terry Lambert tlambert2 at mindspring.com
Wed Mar 26 03:34:03 PST 2003


David J Duchscher wrote:
> > If this is committed before RFC-952 is updated, FreeBSD users
> > can now define host names that break other machines on the net
> > which are strictly conformant to RFC-952.
> 
> Which will just make us behave like rest of the world.  I have tested
> resolvers on Solaris, Windows, MacOS X, MacOS 9, IRIX, Linux, AIX.
> They all will resolve a name with an underscore character.  Only the
> *BSD boxes fail because of the check.

Actually, anyone who took the original ISC code, or the FreeBSD code,
will end up having problems.  Including AIX, Solaris, MacOS X.


> > What is the first maxim of protocol design?
> >
> > "Be generous in what you accept, strict in what you generate".
> 
> Which is why I would argue that the patch should be committed, maybe
> with an option to enable it.  We are talking about the resolver, not a
> DNS or hostname server.  The resolver should resolve the name, be
> generous.  It just depends at what level you apply the maxim.  The
> check should be in the DNS server not in the resolver IMHO.

You apply the maxim to each interface, seperately.  For example,
FreeBSD should not allow the configuration of host names with
"_" in them, but it should, perhaps, permit them to be looked up.

-- Terry


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