Author: Tim Jackson Date: To: exim-users Subject: Re: [exim] reject-log question
Hi Steffen, on Tue, 21 Sep 2004 16:37:25 +0200 you wrote:
> > The underscore in the domain name. It isn't permitted.
> Are you sure?
> Is it better to tell that client to change the name
> OR is it better to allow it?
It is better to tell the client to change the name. By using underscores
they are in a tiny minority of people with broken machines.
> Usually I like it more to keep on standards.
> But I need to be sure, that this is indeed really not permitted.
In a snippet which I believe is relevant here (people who have a more
thorough overview of all the RFCs and their interactions, please correct
me if I'm wrong), RFC2822 says:
"...characters outside the set of alphas, digits, and hyphen MUST NOT
appear in domain name labels for SMTP clients or servers. In particular,
the underscore character is not permitted."
