On 2010-09-30 at 12:31 +0200, Sven Hartge wrote: > They are just not allowed in hostnames. Have a look at
Actually, they are allowed in hostnames, but not if you're intending to use them in an http: URL (and some other URL schemes), or to send mail from that host. RFC 1035 provides a guideline for reducing interoperability problems, but that's not a mandate. The guideline is one it is wise to follow, especially if you ever want to send mail from that host to a system not under your control, or if you want to run a web-server on it, but that does not mean "not allowed". The only current constraints I know of are in RFC 2396, where http is a Server-based Naming Authority and so underscores are disallowed in the URI grammar, and in RFC 5321, where the EHLO/HELO command needs to give a hostname but constrains it to the Domain grammar rule (*sigh*). -Phil -- ## List details at http://lists.exim.org/mailman/listinfo/exim-dev Exim details at http://www.exim.org/ ##
