[Samba] RID/SIDs

John H Terpstra jht at Samba.Org
Fri Jan 28 16:08:08 GMT 2005

On Friday 28 January 2005 07:52, Daniel Corbe wrote:
> Hey
> Can someone point me to a FAQ or an RTFM on what SIDs and RIDs are and
> how to generate them properly?

The SID is generated automatically by Samba. If you change a Samba server name 
or workgroup name a new SID will be generated. This is a strong argument in 
favor of backing up the SID. You can obtain the SID of the Samba server by 

	net getlocalsid
	SID for domain FRODO is: S-1-5-21-726309263-4128913604-1168186429

The SID can be restored by executing:
	net setlocalsid S-1-5-21-726309263-4128913604-1168186429

In a Windows NT4 or ADS domain the RID is generated as the account is created.
The user SID = domain_SID+RID, in the above case the SID for my user account 
is S-1-5-21-726309263-4128913604-1168186429-4214.

Samba uses an algorithm to create a RID from the users UID. The default 
algorithm is:   RID = (UID x 2) + 1000

The best source of documentation for how this is handled in Samba is in the 
source code.

- John T.
John H Terpstra
Samba-Team Member
Phone: +1 (650) 580-8668

The Official Samba-3 HOWTO & Reference Guide, ISBN: 0131453556
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