Characters limitations in the "User Logon Name (more than 20 characters)"

Andrew Bartlett abartlet at
Mon Apr 5 19:58:04 MDT 2010

On Tue, 2010-03-30 at 08:34 +0530, Rohit Rajan wrote:
> Hi,
> We have created a user with the logon name longer than 20 characters, 
> user created successfully, but when trying to logon to windows XP box, 
> user is not able to logon using the "User Logon Name (more than 20 
> characters)" but is able to logon using the "User Logon Name [Pre 
> windows 2000]" which is only 20 characters.
> Is this the normal behavior, i'm not sure but i believe with windows 
> 2003 and windows xp user should be able to logon using the full "User 
> Logon Name (more than 20 characters)".
> I'm using samba Version 4.0.0alpha12-GIT-ba74823 and windows XP service 
> pack 3 with all the patches up2date of windows XP
> Please suggest. seems
to indicate that this attribute should be limited to 20 characters.
Perhaps somewhere a char name[20] still exists in Microsoft's clients.

You may be able to use a longer user name in the userPrincipalName
attribute, but I can assure you that this limitation isn't in Samba (we
just don't ever use fixed length strings except where the protocol
requires it - which isn't the case here). 

Andrew Bartlett

Andrew Bartlett                      
Authentication Developer, Samba Team 
Samba Developer, Cisco Inc.

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