{
    "mode": "man",
    "parameter": "nss",
    "section": "5",
    "url": "https://www.chedong.com/phpMan.php/man/nss/5/json",
    "generated": "2026-10-07T14:37:10Z",
    "sections": {
        "NAME": {
            "content": "nss - Name Service Switch configuration file\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "Each  call  to  a  function  which retrieves data from a system database like the password or\ngroup database is handled by the Name Service Switch implementation in  the  GNU  C  library.\nThe various services provided are implemented by independent modules, each of which naturally\nvaries widely from the other.\n\nThe  default implementations coming with the GNU C library are by default conservative and do\nnot use unsafe data.  This might be very costly in some situations, especially when the data‐\nbases are large.  Some modules allow the system administrator to request taking shortcuts  if\nthese  are  known to be safe.  It is then the system administrator's responsibility to ensure\nthe assumption is correct.\n\nThere are other modules where the implementation changed over  time.   If  an  implementation\nused to sacrifice speed for memory consumption, it might create problems if the preference is\nswitched.\n\nThe  /etc/default/nss file contains a number of variable assignments.  Each variable controls\nthe behavior of one or more NSS modules.  White spaces are ignored.  Lines beginning with '#'\nare treated as comments.\n\nThe variables currently recognized are:\n\nNETIDAUTHORITATIVE = TRUE|FALSE\nIf set to TRUE, the NIS backend for the initgroups(3) function will accept the  infor‐\nmation from the netid.byname NIS map as authoritative.  This can speed up the function\nsignificantly  if  the group.byname map is large.  The content of the netid.byname map\nis used as is.  The system administrator has to make sure it is correctly generated.\n\nSERVICESAUTHORITATIVE = TRUE|FALSE\nIf set to TRUE, the NIS backend for the getservbyname(3) and getservbynamer(3)  func‐\ntions will assume that the services.byservicename NIS map exists and is authoritative,\nparticularly  that  it contains both keys with /proto and without /proto for both pri‐\nmary service names and service aliases.  The system administrator has to make sure  it\nis correctly generated.\n\nSETENTBATCHREAD = TRUE|FALSE\nIf  set  to  TRUE,  the NIS backend for the setpwent(3) and setgrent(3) functions will\nread the entire database at once and then hand out the requests one by one from memory\nwith every corresponding getpwent(3) or  getgrent(3)  call  respectively.   Otherwise,\neach  getpwent(3) or getgrent(3) call might result in a network communication with the\nserver to get the next entry.\n",
            "subsections": []
        },
        "FILES": {
            "content": "/etc/default/nss\n",
            "subsections": []
        },
        "EXAMPLES": {
            "content": "The default configuration corresponds to the following configuration file:\n\nNETIDAUTHORITATIVE=FALSE\nSERVICESAUTHORITATIVE=FALSE\nSETENTBATCHREAD=FALSE\n",
            "subsections": []
        },
        "SEE ALSO": {
            "content": "nsswitch.conf\n\nLinux man-pages 6.7                          2023-10-31                                       nss(5)",
            "subsections": []
        }
    },
    "summary": "nss - Name Service Switch configuration file",
    "flags": [],
    "examples": [
        "The default configuration corresponds to the following configuration file:",
        "NETIDAUTHORITATIVE=FALSE",
        "SERVICESAUTHORITATIVE=FALSE",
        "SETENTBATCHREAD=FALSE"
    ],
    "see_also": []
}