[Samba] UID mapping

Jonathan Buzzard jonathan at buzzard.me.uk
Wed Jun 15 08:29:33 MDT 2011

On Tue, 2011-06-14 at 23:41 +0000, Peter Shevchenko wrote:


> I have been working on exactly this problem. I looked into the 
> rfc2307scheme extensions and it looked like a lot of trouble. The samba 
> HowTo has this to say about it.
> "The use of this method is messy. The information provided in the 
> following is for guidance only and is very definitely not complete. This 
> method does work; it is used in a number of large sites and has an 
> acceptable level of performance." see
> samba.org/samba/docs/man/Samba-HOWTO-Collection/idmapper.html

That is *not* the method I was suggesting to use. I was suggesting using
the idmap_ad backend and winbind directly. No ldap or similar in sight
excepting that AD is ldap.

This is the configuration that I use in smb.conf

# deal with NSS and the whole UID/SID id mapping stuff
        idmap backend = tdb
        idmap uid = 2000000 - 2999999 
        idmap gid = 2000000 - 2999999
        idmap config LIFESCI-AD : backend = ad
        idmap config LIFESCI-AD : schema_mode = rfc2307
        idmap config LIFESCI-AD : readonly = yes
        idmap config LIFESCI-AD : range = 500 - 1999999
        idmap cache time = 120
        idmap negative cache time = 20
        winbind nss info = rfc2307
        winbind expand groups = 2
        winbind nested groups = yes
        winbind use default domain = yes
        winbind enum users = yes
        winbind enum groups = yes
        winbind refresh tickets = yes
        winbind offline logon = false

With nsswitch.conf looking like

passwd:     files winbind
shadow:     files
group:      files winbind

I would say the documentation on how to get his working is not great,
the biggest stumbling block being the need for the non overlapping range
for the plain tdb backend which is all required despite the fact it is
never used.

Yes you need to have winbind running at all times for it to work but it
does work.


Jonathan A. Buzzard                 Email: jonathan (at) buzzard.me.uk
Fife, United Kingdom.

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