Reserved for Windows RIDs for LOCAL, DOMAIN and BUILTIN, staticĭynamic allocation of UIDs and GIDs from LDAP The design with the biggest amount of UIDs and GIDs on 32-bit systems and better can be designed like this: By using:ĭscl /Local/Default -list /Users UniqueID On Mac OS X Apple put everything into the DirectoryService which can be accessed by using dscl. Microsoft RIDs for LOCAL, DOMAIN and BUILTIN, static Unix nobody user and (no)group (Debian and nfsnobody RHEL) Historic reservation for nobody (have not find any use) Used as ID for nobody on some systems (and not used by Microsoft) Red Hat based system nobody user and group ID Unix local users and groups, statically asigned And there is nogroup usage, but also groups that are called nobody.Īll in all a rough overview of what is used where can be created like this: GNU/Linux distribution creators defined the account as 65534, however Red Hat supplied under that ID nfsnobody with another nobody having ID 99. To this confusion was added the use of using -2 for the nobody ID, as was done by the software itself if nobody and nogroup where not defined. However a 16-bit system has another highest number then a 32-bit system: The user nobody and group nogroup came from the NFS software and was defined as being having the highest ID, since the function was oposite to the root. Debian based systems regard all IDs below 1000 to be system IDs, while Red Hat uses all IDs below 500 to be system IDs.Įven more complex is the situation around nobody. POSIX IDs The problem(s)ĭifferent systems are created differently, even within the GNU/Linux world. The only thing we assume is the use of LDAP as the database for atleast the POSIX accounts. This document will try to shed some light on the different systems and how you can arrange your systems such that problems or conflicts are less likely to happen. Next to that a name must be unique too.Īs you can imagine mixing those two systems can be a real challenge. So there can never be 2 identical SIDs within one network. Windows maps account names and group names to a SID, which is globally unique. Due to this setup groupnames and usernames can be the same, or can be different and have the same number. For both groups there is an identical set of numbers that van be used, and they are treated as different entities. The Unix-systems use UID and GID numbers to map usernames and groupnames to numbers. On Windows-like systems (Windows, SAMBA) we have more or less the same problem, which is overcome by using Domains.Īnother type of problem arises if you want to mix Unix-like systems with Windows-like systems. The initial solution was NIS, and today you see more people use LDAP to solve the problem. Unix-like filesystems are often shared through NFS and the problem is how do you make all systems deal with every system having their own user and group database. One of the more complex parts of interoperability is probably dealing with UIDs and GIDs for Unix-like environments and SIDs on Windows-like environments. © 2012 Dennis Leeuw dleeuw at made-it dot com UID, GID, SID and RID UID, GID, SID and RID
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