On August 7, 2008 11:21, in alt.os.linux.slackware, Helmut Hullen
(helmut@hullen.de) wrote:

> Hallo alle miteinander,
>
> "useradd" from "shadow-4.0.3" doesn't allow UPPER letters in login
> names, p.e. "Helmut".
[snip]
> I need UPPER letters p.e. for machine accounts (Samba etc.).

For those, you can manually edit the password file using vipw(1).

> Is there any technical or RFC reason for this behaviour?

Yes, there is a technical reason. One reason is that in Unix (and thus
Slackware Linux), userids are recorded in lower case, so that getty(1) can
determine if an upper-case-only teletype device is being used to log on. If
getty(1) detects uppercase in the username, it switches the line
conditioning mode so that all output lowercase is converted to upper case,
and all input uppercase is converted to lowercase.

--
Lew Pitcher

Master Codewright & JOAT-in-training | Registered Linux User #112576
http://pitcher.digitalfreehold.ca/ | GPG public key available by request
---------- Slackware - Because I know what I'm doing. ------

Lew Pitcher wrote:
> If getty(1) detects uppercase in the username, it switches the line
> conditioning mode so that all output lowercase is converted to upper case,
> and all input uppercase is converted to lowercase.

I _think_, but cannot test this, that this behaviour is invoked
(with a normal getty, the agetty Slackware is using doesn't do
this) when the FIRST letter of the typed-in login name is a capital.
Getty then assumes that the user can NOT type in lower case chars,
so will convert everything the user types to lower case (but ECHO
it in upper case).
Note, if you manage to logon this behaviour will be for the whole
session, not just the login/password (the iuclc parameter to stty
see 'man stty', will be set by getty).

Of course graphical login managers (like kdm) don't have this
problem, as they're used only by the local keyboard, not a
"remote terminal for which attributes are unknown".
--
************************************************** *****************
** Eef Hartman, Delft University of Technology, dept. SSC/ICT **
** e-mail: E.J.M.Hartman@tudelft.nl, fax: +31-15-278 7295 **
** snail-mail: P.O. Box 5031, 2600 GA Delft, The Netherlands **
************************************************** *****************

Eef Hartman wrote:
> Lew Pitcher wrote:
>> If getty(1) detects uppercase in the username, it switches the line
>> conditioning mode so that all output lowercase is converted to upper case,
>> and all input uppercase is converted to lowercase.
>
> I _think_, but cannot test this, that this behaviour is invoked
> (with a normal getty, the agetty Slackware is using doesn't do
> this) when the FIRST letter of the typed-in login name is a capital.
> Getty then assumes that the user can NOT type in lower case chars,
> so will convert everything the user types to lower case (but ECHO
> it in upper case).
> Note, if you manage to logon this behaviour will be for the whole
> session, not just the login/password (the iuclc parameter to stty
> see 'man stty', will be set by getty).

The agetty Slackware is using *does* do this, as the test below shows.

Welcome to Linux 2.6.24.5-smp (tty5)

lankhmar login: KEES
PASSWORD:
LOGIN INCORRECT

LANKHMAR LOGIN:


This is on a Slackware 12.1 VC. I'm quite sure i've seen this recently
on a Slackware 10.2 too.


An other problem with upper case chars in user names is mail delivery.
Most -if not all- email software will handle the "local part" of an
email address (i.e. the string before the @ sign) in a case insensitive
way when delivering to local mailboxes.
At least sendmail will convert SomeUser@your.domain or
SOMEUSER@your.domain to someuser@your.domain before it selects the
mailbox, or alias, to deliver to.

If you only want to use upper or mixed case names for computer
accounts in samba, then email delivery is probably not a concern
though.


Regards,

Kees.

--
Kees Theunissen.

On Thu, 7 Aug 2008, Lew Pitcher wrote:

>
> On August 7, 2008 11:21, in alt.os.linux.slackware, Helmut Hullen
> (helmut@hullen.de) wrote:
>
>> Hallo alle miteinander,
>>
>> "useradd" from "shadow-4.0.3" doesn't allow UPPER letters in login
>> names, p.e. "Helmut".
> [snip]
>> I need UPPER letters p.e. for machine accounts (Samba etc.).
>
> For those, you can manually edit the password file using vipw(1).
>
>> Is there any technical or RFC reason for this behaviour?
>
> Yes, there is a technical reason. One reason is that in Unix (and thus
> Slackware Linux), userids are recorded in lower case, so that getty(1) can
> determine if an upper-case-only teletype device is being used to log on. If
> getty(1) detects uppercase in the username, it switches the line
> conditioning mode so that all output lowercase is converted to upper case,
> and all input uppercase is converted to lowercase.
>

Also because many/most/all MTA's don't distinguish between upper and
lowercase, so, by allowing two separate system users -
'helmut' and 'Helmet', the MTA will be confused and each may get the
others mail, IIRC MTA's are not teh only thing that can get confused
either.


--
Cheers
Res
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a nicer place.

On 2008-08-07, Eef Hartman wrote:
>
> Of course graphical login managers (like kdm) don't have this
> problem, as they're used only by the local keyboard, not a
> "remote terminal for which attributes are unknown".

I am pretty sure kdm can be configured to listen on the network for
XDMCP connections. Then again, if a machine can do XDMCP, it should be
able to send both upper and lower-case characters.

--keith


--
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Hallo, Keith,

Du meintest am 07.08.08:

>> Of course graphical login managers (like kdm) don't have this
>> problem, as they're used only by the local keyboard, not a
>> "remote terminal for which attributes are unknown".

> I am pretty sure kdm can be configured to listen on the network for
> XDMCP connections. Then again, if a machine can do XDMCP, it should
> be able to send both upper and lower-case characters.

Thank you all - now I'm confused on a higher level.

When working with samba I'm trained to write then Logon names for
machine accounts with UPPER letters, many examples also propose that.

And some other distributions have a "useradd" which allows that.

I will ask in the Samba mailinglist wether it is necessary.

Viele Gruesse
Helmut

"Ubuntu" - an African word, meaning "Slackware is too hard for me".

On Fri, 8 Aug 2008, Helmut Hullen wrote:
>> be able to send both upper and lower-case characters.

>
> Thank you all - now I'm confused on a higher level.
>



--
William Hunt, Portland Oregon USA

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On 2008-08-07, Helmut Hullen wrote:
> I need UPPER letters p.e. for machine accounts (Samba etc.).

No you don't, at least not with samba. As far as Windows is concerned,
there is no difference between 'a' and 'A'. Just enter all your
machine names in with lowercase letters and everything will be fine.

- --
It is better to hear the rebuke of the wise,
Than for a man to hear the song of fools.
Ecclesiastes 7:5
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