[NTLUG:Discuss] Number of groups per user in Linux

[Chris Cox]

Greg Edwards wrote:
...
> 
> Just wondering how well Linux handles sub-groups?
> 
> A sub-group being where username belongs to group A, and group A belongs 
> to group B, and group B belongs to group C, etc..  Does the limit apply 
> to all groups inclusive, or each group independently?
> 

There is no such animal AFAIK.  Well... there are similar things but it
depends on usage (e.g. netgroups, nested groups in ldap, etc.).

So a user can belong to 16 groups safely.  32 a bit less safely.
And 65535 groups if all Linux.

I think a lot of the expansion of NGROUPS_MAX was done to support
the smashing that goes on when converting Windows ids via winbind
(samba).

If somebody knows different, speak up.  I deal with a lot of
Unix...  so I can't just consider the Linux-only side.  Maybe
Linux has something like nested groups... but not AFAIK.