mail forwarding problem

[Bruno Wolff III]

On Fri, May 25, 2007 at 11:17:07 -0500,
  "Mikkel L. Ellertson" <mikkel at infinity-ltd.com> wrote:
> By default, e-mail addresses are converted to all lower case. You
> will have problems with mixed or upper case user names and/or e-mail
> addresses. It is possible to reconfigure your mail local mail server
> to preserve the case, but it would be better to change your user
> name to all lower case. (Mixed case user names break a bunch of
> specifications...)

The RFCs specify that the local part of email addresses are case sensitive.
On many hosts case mapping is done when delivering the message locally,
but no MTAs should be messing with it until that point.