A web server receives requests for resources (HML documents, images, etc). If it can send them it includes a success code 200. But if it can't find the resource, it sends a "404 not found" message. Each request and its status is recorded in the log file. A typical 404 message line is
which includes the requesting IP address, the date, the HTTP request, the protocol version,
"404" and information about the requesting agent. In the example, the resource
that cannot be found is the seventh field
126.96.36.199 - - [31/May/2009:05:55:08 +1000] "GET /java/tut/tut2.sgml-109.html HTTP/1.0" 404 308 "-" "Mozilla/5.0 (compatible; Yahoo! Slurp/3.0; http://help.yahoo.com/help/us/ysearch/slurp)"
Any 404 error either represents a fault on the Web site, or an attack trying to probe the site for potential weak points. Write
Two computers need to be set up to provide a DMZ (demilitarised zone) for
your network. The first "exterior firewall" connects directly to the internet.
The second "interior firewall" acts as the gateway for the internal network.
In the DMZ are computers running services which shoud be visible
from the outside and inside, such as HTTP and email.
(Figure from www.oracle.com)
The external world should only be able to see the servers in the DMZ. The internal world should be able to see these servers too, but also be able to connect to servers in the outside world.
Describe the firewall setup on the interior and exterior firewall machines to allow this visibility. Give simple english forms of the rules on each firewall.
You have multiple users on your computer. There are a number of local programs
which are all in the directory
/usr/local/bin. All the users
need to get access to all the programs in this directory, so that when they
try to execute a command it will be looked for in that directory.
The minimal space for a Linux system is currently about 4Gb
but gets bigger with each new version.
Swap space is usually set
to the same size as RAM. Files such as log files that grow are kept in
/var/log. These are usually less than 1Gb in total.
Local system files are kept in
They can use the same size as the Linux system itself, at maximum.
The rest of the space can be given to user files in
You have a system with 2Gb RAM and 500Gb hard disk. You will be running HTTP and email servers.