Chapter 19: Userids and Groupids

Unix identifies users by numeric userids and groupids, referred to here as UIDs and GIDs. These range from 0 to 32767. (Recently the upper limit has been doubled by some vendors but it seems prudent to ignore this until all vendors support the larger range.) Usernames are the user-friendly interface to UIDs. It is anticipated that potential problems with transfer of data between systems will be avoided if any given UNIX user has the same UID on all the systems anywhere in NERC. Once a UID has been allocated to a user at one site, that UID will not be allocated to any other user. If an account for that user is created on another system, anywhere in NERC, it will be given the same UID (and similarly for UNIX groups and GIDs). To that end the set of permitted UIDs and GIDs has been partitioned between the various NERC sites as given in the list below. The list associates a range with each site. UIDs and GIDs should be chosen from the range for the site. UIDs and GIDs form disjoint spaces, so there is no prohibition against using a number, 20000 say, for both a UID and a GID. Note that users may be members of more than one group and hence be associated with more than one GID (although on each system each user will have a default group/GID assigned upon logging in). It is permissible to belong to a group, and hence use a GID, which is based and administered at another site. There are also ranges which are not associated with any site in particular. 0-99 is a good example; this range is identified as 'reserved' by the UNIX manuals. Another such range is NCS roles for NCS accounts such as ORACLE. Similar ranges have been set aside for each of the Earth Sci., Marine Sci., and TFS directorates. The range 'Free' is unconstrained. Anybody can do anything they like with it on the understanding that it is realised that UIDs and GIDs in this range will, in general, mean something else on different systems.

Local Support are responsible for the allocation of ids from within the range allocated to their site(s). Under some circumstances ( e.g. when a NERC unit is merged with a University or a University department joins a NERC institute ) it may be necessary to use the University range instead.

Range allocated

Range allocated

To

Number

Reserved by UNIX

0

99

100

Free

100

999

900

NCS roles

1000

1499

500

Earth Science roles

1500

1999

500

Marine Science roles

2000

2499

500

TFS roles

2500

2999

500

Rutherford

3000

3499

500

Belfast

3500

3699

200

Gilmerton

3700

3899

200

Hartland

3900

4099

200

Newbattle Abbey

4100

4299

200

Unallocated

4300

4999

 

Cambridge

5000

7399

2400

Windermere

7400

7599

200

Unallocated

7600

7999

 

Keyworth

8000

9999

2000

London

10000

10499

500

Newcastle

10500

10699

200

Sheffield

10700

10899

200

Unallocated

10900

10999

 

Edinburgh

11000

12999

2000

Grange Terrace

13000

13199

200

Bush

13200

13599

400

Oban

13600

13799

200

Dundee

13800

13999

200

East Kilbride

14000

14199

200

Eskdalemuir

14200

14399

200

Lerwick

14400

14599

200

Unallocated

14601

14999

 

Plymouth

15000

16999

2000

Plymouth University

17000

17199

200

Wareham

17200

17399

200

Furzebrook

17400

17599

200

Exeter

17600

17799

200

SOC

17800

17999

200

Bidston

18000

19999

2000

SOC

20000

21999

2000

Hambledon

22000

22199

200

IVEM 

22200

22399

200

Bangor

22400

22599

200

Aberystwyth

22600

22799

200

Plynlimon

22800

22999

200

Swindon

23000

24999

2000

Wallingford

25000

26999

2000

SOC

27000

27999

1000

Reading

28000

28999

1000

Southampton University

29000

29199

200

SOC

29200

30999

1800

Unallocated

31000

32767

 

 

Note that the old Merlewood and Monkswood blocks have been merged into the BAS Cambridge block, and the Banchory block merged into the Bush CEH Edinburgh block.

 

Allocated UIDs and GIDs

The following userids have been allocated from the NCS roles range. This list is maintained by Applications Group heads, for the package ids, and by Systems Group heads for the rest. Mail your nearest central site for an up-to-date list.

Username

UID

Group

ncs

1000

ncs

admin

1001

admin

operator

1002

operator

postmaster

1003

admin

uniras

1004

packages

oracle

1005

dba

sas

1009

packages

bart

1010

packages

nag

1011

packages

aptest

1012

test

grafix 

1016

packages

arc 

1017

packages

wp

1018

packages

arcims

1019

packages

explorer 

1020

packages

arcview 

1021

packages

ismd 

1022

packages

ileaf

1023

packages

licman

1024

packages

pvwave

1025

packages

vista

1026

packages

minitab

1027

packages

status

1028

packages

orasave

1029

packages

nvision

1030

packages

genstat

1031

packages

glim

1032

packages

splus

1033

packages

oralib

1034

packages

pnms

1035

pnms

avs

1036

packages

assyst

1037

packages

assystadm

1038

packages

assystad

1039

packages

sculptor

1040

packages

maple

1041

packages

mathematica

1042

packages

matlab

1043

packages

erdas

1044

packages

ncsdemo

1045

packages

visilog

1046

packages

coshh

1047

packages

medley

1048

packages

idl

1049

packages

molecular

1050

packages

sgks

1051

packages

earth

1052

packages

nexpert

1053

packages

naggraf

1054

packages

wispps

1055

packages

itsstar

1056

packages

sde

1057

packages

wuftp

1058

packages

oracas

1059

dba

local

1100

ncs

susa

1101

ncs

systest

1102

test

syshelp 

1103

ncs

nrsfile 

1105

ncs

nercman 

1107

ncs

confman 

1108

ncs

secman 

1109

ncs

nercnews 

1110

ncs

squid

1111

packages

bootstrap

1112

ncs

codadmin

1113

ncs

cronchk

1114

ncs

globus

1115

packages

brewbuilder

1116

packages

networker

1117

packages

sshd

1119

sshd

mysql

1120

mysql

gaspmig

1121

mig

manmig

1122

mig

gabmig

1123

mig

ftp

1150

ftp

ftpadmin

1198

ftp

ftpman

1199

ftp

reserved for finance computers

1200

GIDs 1200 to 1299  reserved

reserved for finance computers

1200 to 1299 reserved

GIDs 1200 to 1299  reserved

reserved for finance computers

1299

GIDs 1200 to 1299  reserved

news

8015

ncs

The following groups have been allocated from the NCS roles range. This list is maintained by Applications Group heads, for the package ids, and by Systems Group heads for the rest. Mail your nearest central site for an up-to-date list

Groupname

GID

ncs

1000

admin

1001

graphics

1002

operations

1003

dba (data base admin)

1004

pnms

1011

sdba (Status data base admin)

1012

test

1102

comms

1103

ftp

1104

ftpadmin

1105

tssftp

1106

sshd

1119

mysql

1120

mig

1121

reserved for finance computers

1200

reserved for finance computers

1200 to 1299 reserved

reserved for finance computers

1299