Resolver Issues (non valid hostname characters)
David J Duchscher
daved at nostrum.com
Wed Mar 26 04:33:57 PST 2003
On Tuesday, March 25, 2003, at 09:32 PM, Terry Lambert wrote:
> 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.
Unless they have modified the code which all the above OSes seem to
have done since they do not show the behavior.
>>> 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.
I can agree with this statement. Unfortunately, FreeBSD doesn't do this
in many ways. Example, you can set a hostname with a underscore in it.
You can even use an underscore in the name in the host file and
will work. You just can't look up the name via DNS.
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