underscores in hostname

Jim Reid jim at rfc1035.com
Fri Mar 23 15:13:35 UTC 2001

>>>>> "Pete" == Pete Peterson <petersonp at genrad.com> writes:

    Pete> When I first ran into this problem after inheriting a zone
    Pete> with bad names, I discovered that BIND would wouldn't accept
    Pete> A-records with underscores, but WOULD accept CNAMES with
    Pete> underscores.  I made a script which changed the underscores
    Pete> to hyphens and then added a CNAME with the underscored
    Pete> version.  This gave time to phase out the bogus names while
    Pete> keeping BIND happy.  This still works fine with 8.2.3; I
    Pete> haven't any 9.x nameservers yet.

BIND9 does not enforce hostname checking. There are two reasons for
this. The first is that it should be up to applications to apply
whatever checking criteria they choose on the names being looked up.
This should not be a job for the name server. Secondly, there's a good
chance that the encoding schemes for international domain names will
mean that an ASCII rendition of a Japanese domain name (say) could
well be an illegal hostname according to RFC1123.

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