On Thu, 2010-09-30 at 08:49 +0200, Thomas Hochstein wrote: > Wasn't it disallowed to use underscores in DNS entries?
Host and domain names are defined in RFC1034 as follows: "The labels must follow the rules for ARPANET host names. They must start with a letter, end with a letter or digit, and have as interior characters only letters, digits, and hyphen. There are also some restrictions on the length. Labels must be 63 characters or less." However many subsequent RFCs exist which update this to extend to other RR types, such as the TXT RR (defined in RFC1035) which is defined as: "TXT-DATA One or more <character-string>s." And a character-string is further defined in RFC1035 in a very long paragraph which I'll not quote here. In short, a dnslist can be used to contain items which are neither host nor domain names; ergo characters not permissible in those items should be permissible to enable the lookup of records such as they type Mike originally mentioned. Apologies if that's a bit long-winded but it might help others who come along later and look in the archives! Graeme
signature.asc
Description: This is a digitally signed message part
-- ## List details at http://lists.exim.org/mailman/listinfo/exim-dev Exim details at http://www.exim.org/ ##
