There are a lot of things that the RFCs say that Exim exim accepts. If
Exim enforced all the rules no one would be able to use it.
Adrian Phillips wrote:
>>>>>>"Marc" == Marc Perkel <marc@???> writes:
>>>>>>
>>>>>>
>
> Marc> In this case the server was auction.co.kr which is probably
> Marc> not a trivial server. I think that exim rejecting an
> Marc> underscore in the HELO is a bug and something that shouldn't
> Marc> happen by default even if it is technically not supposed to
> Marc> be there.
>
>Wrong, no bug here - read RFC2821 4.1.2 :--
>
> appear in domain name labels for SMTP clients or servers. In
> particular, the underscore character is not permitted. SMTP servers
> that receive a command in which invalid character codes have been
> employed, and for which there are no other reasons for rejection,
> MUST reject that command with a 501 response.
> ^^^^
>
>Sincerely,
>
>Adrian Phillips
>
>
>
