Operating system security precaution brief: Linux Chapter _unix Linux

Linux as a free, open symbol, more and more users of the attention, but the real use of less personal users, mainly because of its system characteristics, and the surrounding software developers less, so that it only in the server system in the field of popularity. It's security protection, I do a little introduction:

1. Prohibit access to important files

Linux is not like windows, it not only publishes source code, its core program can also be arbitrarily modified according to user needs, For some key files in the system, such as inetd.conf and lilo.conf, can also be modified (telnet user), in order to protect the system security, you can modify its properties in advance to prevent illegal intrusion and modification.

First into the Linux command interface, input instructions:

# chmod 600/etc/inetd.conf

Change the file property to 600.

And then enter the directive:

# chattr +i/etc/inetd.conf

Ensure that the owner of the file is root.

In this way, any changes to the document will be prohibited. Only to pass the instructions again:

# chattr-i/etc/inetd.conf

Root resets the reset flag before it can be modified.

2. Prohibit remote access

The 2 files in Linux allow and disallow remote host access to local services through the/etc/hosts.allow and/etc/hosts.deny. The method is: Enter the Linux command interface, pull up Hosts.deny file, add the following instructions:

# Deny access to everyone.

All:all@all

All services are prohibited for all external hosts unless specified by the Hosts.allow file.

In the Hosts.allow file, add the host methods that allow access as follows:

Pull up the Hosts.allow file and add the following instructions:

#Just An example:

http:192.168.1.8 yanghao.com

This means that an IP address is allowed to access the HTTP service as a client for a machine with a 192.168.18 and host name of Yanghao.com.

The system security protection way, the author introduced here, cannot be exhaustive. Users who use Windows XP and other "NT core" systems should pay more attention to security issues and, when using XP, it is best to open their own firewalls (Microsoft also sets the firewall to open in the new release of Windows XP). Users of any system should have certain security knowledge, such as: Do not easily disclose their network and system information, do not carry out the procedures of unknown origin. A secure system environment is built on its own.
(Source: China computer Education newspaper)