I don't think that XMail is still being developed and maintained.
But, just in case: a user of mine sent an email to
<first.l...@university.ac.uk?> (note the trailing question mark).
XMail tried to deliver and failed for the following reason:
ErrCode = -109
SMTP-Error = "Unable to get UDP DNS response"
Since I don't think the address should have passed the syntax check, I
googled a bit and found that the address is RFC5322 compliant
(http://tools.ietf.org/html/rfc5322#section-3.4.1) but contains domain
characters that are not allowed by DNS. Section 3.4.1 says that
Note: A liberal syntax for the domain portion of addr-spec is
given here. However, the domain portion contains addressing
information specified by and used in other protocols (e.g.,
[RFC1034], [RFC1035], [RFC1123], [RFC5321]). It is therefore
incumbent upon implementations to conform to the syntax of
addresses for the context in which they are used.
So, I think in general XMail should not accept such addresses (and, more
generally, the reference for syntax check should be RFC5321 more than
Final note: this may be my last message on the list; my server will
close in a few days, and that will be the end of my (very good)
experience with XMail. I leave the suggestion to anybody willing to keep
xmail mailing list