pls help: numeric username - Redhat

This is a discussion on pls help: numeric username - Redhat ; Hi, all, Our management want to use all numeric username in our systems which runs RedHat/CentOS/Fedora. I'd like to know if there is any restriction on the username format. Would anyone please help? Thanks a lot. /ST Wong...

+ Reply to Thread
Results 1 to 6 of 6

Thread: pls help: numeric username

  1. pls help: numeric username

    Hi, all,

    Our management want to use all numeric username in our systems which
    runs RedHat/CentOS/Fedora. I'd like to know if there is any
    restriction on the username format.

    Would anyone please help?

    Thanks a lot.
    /ST Wong


  2. Re: pls help: numeric username

    In fact no problem but the convention whith Unix/Linux is using letters . .
    ..
    When you look for the PID of your username ? I think it's a problem to
    recognize which is PID or Unsername ? it's dangerous ?


    Claude

    a écrit dans le message de news:
    1174060055.727602.247230@l75g2000hse.googlegroups. com...
    > Hi, all,
    >
    > Our management want to use all numeric username in our systems which
    > runs RedHat/CentOS/Fedora. I'd like to know if there is any
    > restriction on the username format.
    >
    > Would anyone please help?
    >
    > Thanks a lot.
    > /ST Wong
    >




  3. Re: pls help: numeric username

    On Mar 25, 4:05 pm, " claude" wrote:
    > In fact no problem but the convention whith Unix/Linux is using letters . .
    > .
    > When you look for the PID of yourusername? I think it's a problem to
    > recognize which is PID or Unsername ? it's dangerous ?
    >
    > Claude


    I voiced out it's bad idea to use all numbers in username but
    managers insist (can't understand why...). I
    thus try to collect proof to against their idea. Although still can't
    find a doc stating it clearly, I found some tools dislike numeric
    usernames. Will let managers know the down side of numeric usernames
    as you all mentioned. See if life can become easier here... :-|

    Thanks a lot.
    /st


  4. Re: pls help: numeric username

    wst305@gmail.com wrote:
    > On Mar 25, 4:05 pm, " claude" wrote:
    >
    >>In fact no problem but the convention whith Unix/Linux is using letters . .
    >>.
    >>When you look for the PID of yourusername? I think it's a problem to
    >>recognize which is PID or Unsername ? it's dangerous ?
    >>
    >>Claude

    >
    >
    > I voiced out it's bad idea to use all numbers in username but
    > managers insist (can't understand why...). I
    > thus try to collect proof to against their idea. Although still can't
    > find a doc stating it clearly, I found some tools dislike numeric
    > usernames. Will let managers know the down side of numeric usernames
    > as you all mentioned. See if life can become easier here... :-|
    >
    > Thanks a lot.
    > /st
    >

    Hello ST,


    Following shows that a user 12345678 can be added and given a password
    on RHEL 5 Server

    [root@myhost ~]# useradd 12345678
    [root@myhost ~]# grep 12345678 /etc/passwd
    12345678:x:503:504::/home/12345678:/bin/bash
    [root@myhost ~]# passwd 12345678
    Changing password for user 12345678.
    New UNIX password:
    BAD PASSWORD: it is too simplistic/systematic
    Retype new UNIX password:
    passwd: all authentication tokens updated successfully.


    The only issue you will get if a user is deleted and some directories
    will loose there owners.

    Finding files without an owner is harder, if the numerical value of the
    usernames have the same number of digit as the number of digits of an
    userid.


    Kind regards,


    Jan Gerrit

  5. Re: pls help: numeric username

    On Tue, 27 Mar 2007 04:40:15 -0700, wst305@gmail.com wrote this:

    > On Mar 25, 4:05 pm, " claude" wrote:
    >> In fact no problem but the convention whith Unix/Linux is using letters
    >> . . .
    >> When you look for the PID of yourusername? I think it's a problem to
    >> recognize which is PID or Unsername ? it's dangerous ?
    >>
    >> Claude

    >
    > I voiced out it's bad idea to use all numbers in username but
    > managers insist (can't understand why...). I thus try to collect proof
    > to against their idea. Although still can't find a doc stating it
    > clearly, I found some tools dislike numeric usernames. Will let managers
    > know the down side of numeric usernames as you all mentioned. See if life
    > can become easier here... :-|
    >
    > Thanks a lot.
    > /st


    In the big scheme it's only risky because it's easier to guess numeric
    passwords than alpha-numeric passwords, otherwise there's no difference
    between 1234 and j47n as userids.

    Just make sure username is linked to userid in passwd file and keep super
    secret list cross-referencing user id to user name. Maybe variable
    length numeric ids, ie, John Doe = 12345678, Abraham Lincoln =
    123456789012345

    And don't use SSN, employee id or any type of official serial numbers.

  6. Re: pls help: numeric username

    In our case, the case is worse since the numeric username starts with
    0. Found that quota/edquota use strtol to check input, and thus
    username starts with 0 as octal and the displayed username/uid will be
    incorrect unless there is '8' or '9' in the numeric username. :-| I
    don't think this is a bug, just due to the awkard username format
    we're using ...

    Anyway, seems username handling method in different tools varies: some
    accepts numeric usernames, some dislike it (e.g. system-config-users),
    while some like it if not uncommon format are used...

    Thanks again for all replied.
    /ST


+ Reply to Thread