Recommendations for DNS

Thu May 14 16:26:53 CEST 1998

>   From owner-dns-wg at ripe.net Thu May 14 15:54:09 1998
>   From: Hans Niklasson <hasse at swip.net>

Hans,

> Illegal characters: 
>         
>         Only a-z , 0-9 and - is valid to use. All other characters is
>         illegal and can cause the resolving to fail.

I think it is worthwile at least mentioning that this restriction applies
to _hostnames_ (e.g. right hand side of NS or MX records). This does not
necessarily apply elsewhere. The third document you give as additional
reading (draft-ietf-dnsind-classless-inaddr-04.txt) does use a character
that is not in the set above (slash).

This topic is very well clarified in RFC 2181 chapter 11. (Name syntax).

Best regards,
Janos