Basic IPv4 Reference

March 27, 2007 at 12:17 am

For all those who don’t like to remember the details I have included my quick reference to IPv4. Its not full fledged but can offer some pointing in the right direction. IPv4 is the fourth iteration of the Internet Protocol (IP) and is the most widely deployed. If you want some ugly history details you can always refer to IETF RFC (791). Otherwise just know IPv4 is a data oriented protocol to be used on packet switched internetworks such as ethernet.
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Category: Networking 101

Deleting Files/Directories X Number of Days or Older in Linux

March 15, 2007 at 11:37 pm

In order to help keep your servers disk space free, often times you will need to delete files and directories of a certain age or older. You can do this various ways however using the find command can be a very effective technique. Always use caution when doing mass deletes, or you may end up with to much free space…
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Category: Systems 101

How to secure DNS (BIND 9) on Linux using a chroot jail

March 12, 2007 at 4:39 pm

Since DNS is within the top 5 network security attack targets I have written the below dirty how to on implementing a secure BIND 9 installation.

This document explains how to configure BIND in a “chroot jail” which means BIND cannot see or access files outside its own directory structure. Also we will configure it to run as a non root user bind to avoid root powers.

When you run BIND in a chroot jail, the BIND process is unable to see any part of the filesystem outside the jail. In BIND’s eyes, the contents of the jail directory will appear to be / or the root directory. All things outside this directory will not have access to it.

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Category: Systems 101