------------ Original Message ------------ > Date: Saturday, April 30, 2016 12:44:52 -0700 > From: Alice Wonder <alice at domblogger.net> > > On 04/30/2016 12:22 PM, Gordon Messmer wrote: >> On 04/30/2016 11:28 AM, Alice Wonder wrote: >>> Is there any advice on characters to allow in usernames? >> ... >>> I don't think a whitelist alphabet is best approach because of >>> people with names that are not spelled with Latin characters. >>> >>> Is there an existing blacklist of characters that technically >>> legal but are generally avoided in e-mail addresses? >> >> The RFC uses a list of allowed characters, and so must you. > > For e-mail sent to people, yes. > > But for what usernames are allowed when creating an account, I > don't see why blacklisting characters that are not allowed in a > username is a standards problem. You can set any rules you want for what your local users can use for their accounts -- within the constraints of the mail RFCs. You just have to accept mail with and allow your users to send to any RFC compliant email address.