[CentOS] E-mail advice sought

Sun May 1 12:23:10 UTC 2016
Alice Wonder <alice at domblogger.net>

On 05/01/2016 05:10 AM, Alice Wonder wrote:
> On 05/01/2016 01:57 AM, Leon Fauster wrote:
>> Am 01.05.2016 um 06:43 schrieb Alice Wonder <alice at domblogger.net>:
>>> On 04/30/2016 08:56 PM, Gordon Messmer wrote:
>>>> On Sat, Apr 30, 2016 at 12:44 PM, Alice Wonder
>>>> <alice at domblogger.net> wrote:
>>>>> 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.
>>>> That's not how the RFC rules are defined.  But, rather than argue that
>>>> point at length, I'd point out that Open Group standards for usernames
>>>> are simple and will comply with the SMTP RFCs:
>>>> http://pubs.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap03.html#tag_03_426
>>>> That is, [A-Za-z0-9._][A-Za-z0-9._-]
>>>> _______________________________________________
>>>> CentOS mailing list
>>>> CentOS at centos.org
>>>> https://lists.centos.org/mailman/listinfo/centos
>>> I think there is a mis-understanding.
>>> All I was looking for was if there was a common set of characters
>>> typically blasted from new usernames *on the domain being set up*
>>> I have no desire to refuse delivery to any valid e-mail address.
>>> For example, avoiding spaces in usernames for addresses on the system
>>> is handy because it avoids bugs where the path to the mailbox on the
>>> filesystem isn't properly quoted.
>>> So user names on the system won't be allowed to have spaces even
>>> though they are legal when within quotes or escaped.
>>> That's all I was looking for, was experience on what legal characters
>>> to avoid allowing users to have for the mailbox portion of their
>>> e-mail address, the username.
>>> Of course I have no desire to restrict who they can send to if it is
>>> a legal address.
>> blacklisting is not a good practice, use the suggested whitelist ...
> I think this is my autism coming in to play, I think what is very clear
> to me I just am not able to adequately communicate because clearly
> people are not even remotely grasping what I am trying to convey.

Basically whether it is a white list or a black list doesn't matter.

One is just the complement set of the other.

It's the set I'm after. Or its complement. I don't care. Not whether my 
code should use set A or its complement.