On 15/05/2013 3:10 AM, Rick Moen wrote:
Quoting Andrew McGlashan (andrew.mcglashan@affinityvision.com.au):
Already, the RFC takes away capitalization from emails, unless I am mistaken, but periods should be accepted as one of any of the available "normal" characters for the local part of the email address.
I can't find the RFC reference, but left-hand-side (local part) portions of e-mail addresses should be left intact and not lowercased, as there have been Internet-connected systems for which the local part is case-sensitive.
I think I've seen case as being important too, with some old Windows mail system (many years ago), but it seemed to be an aberration to every other mail system I've seen. My exim4 seems to completely ignore case when I do testing with: exim4 -bt aaa@somedomain.com exim4 -bt aAa@somedomain.com - but I'm not positive that using "-bt" with exim will always give the actual end result that you would get through normal delivery. Okay, I just found some more information: http://www.exim.org/exim-html-current/doc/html/spec_html/ch-domain_host_addr... <quote> 20. Case of letters in address lists Domains in email addresses are always handled caselessly, but for local parts case may be significant on some systems (see caseful_local_part for how Exim deals with this when routing addresses). However, RFC 2505 (Anti-Spam Recommendations for SMTP MTAs) suggests that matching of addresses to blocking lists should be done in a case-independent manner. Since most address lists in Exim are used for this kind of control, Exim attempts to do this by default. </quote> So, it is possible on modern systems. My son wanted to have a "Unicode Character 'ZERO WIDTH NO-BREAK SPACE'" local part for his email, thus using just an empty "like" zero-space character, but it was too awkward ... and I decided not to bother futzing too much with the idea. http://www.fileformat.info/info/unicode/char/feff/index.htm Cheers A.