Redhat Linux Network Security

Discussion in 'Computer Support' started by troy.john78, Dec 3, 2007.

  1. troy.john78

    troy.john78 Guest

    Redhat Linux Network Security

    Covering everything about security would take several volumes of
    books, so we can only look

    at the basics. We can take a quick look at the primary defenses you
    need in order to protect

    yourself from unauthorized access through telephone lines (modems), as
    well as some aspects

    of network connections. We won't bother with complex solutions that
    are difficult to

    implement because they can require a considerable amount of knowledge
    and they apply only to

    specific configurations.

    Instead, we can look at the basic methods of buttoning up your Linux
    system, most of which

    are downright simple and effective. Many system administrators either
    don't know what is

    necessary to protect a system from unauthorized access, or they have
    discounted the chances

    of a break-in happening to them. It happens with alarming frequency,
    so take the industry's

    advice: Don't take chances. Protect your system.

    Weak Passwords

    Believe it or not, the most common access method of breaking into a
    system through a

    network, over a modem connection, or sitting in front of a terminal is
    through weak

    passwords. Weak (which means easily guessable) passwords are very
    common. When these are

    used by system users, even the best security systems can't protect
    against intrusion.

    If you're managing a system that has several users, you should
    implement a policy requiring

    users to set their passwords at regular intervals (usually six to
    eight weeks is a good

    idea), and to use non-English words. The best passwords are
    combinations of letters and

    numbers that are not in the dictionary.

    Sometimes, though, having a policy against weak passwords isn't
    enough. You might want to

    consider forcing stronger password usage by using public domain or
    commercial software that

    checks potential passwords for susceptibility. These packages are
    often available in source

    code, so they can be compiled for Linux without a problem.

    File Security

    Security begins at the file permission level and should be carried out
    carefully. Whether

    you want to protect a file from snooping by an unauthorized invader or
    another user, you

    should carefully set your umask (file creation mask) to set your files
    for maximum security.

    Of course, this is really only important if you have more than one
    user on the system or

    have to consider hiding information from certain users. However, if
    you are on a system with

    several users, consider forcing umask settings for everyone and set

    permissions only for the user, and no permissions for everyone else.
    This is as good as you

    can get with file security.

    For very sensitive files (such as accounting or employee information),
    consider encrypting

    them with a simple utility. There are many such programs available.
    Most require only a

    password to trigger the encryption or decryption.

    More information visit
    troy.john78, Dec 3, 2007
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