Cisco ASA 5505 Configuration: Definition & Purpose

Instructor: Sudha Aravindan

Sudha has a Doctor of Education degree in math education and is currently working as a Information Technology Specialist.

In this lesson, we will learn about the need for firewall and security and how to configure the Cisco Adaptive Security Appliance(ASA) 5505 for proactive firewall and antivirus defense, for a small network, thereby stopping the spread of attacks before they propagate through the network.

Cisco Adaptive Security Appliance

Emma is the assistant at a day care center. One afternoon as she was browsing the net for a gift for the parents meet and greet event, she unknowingly clicked on a link that crashed her computer. Matt, the IT tech support identified the link as malicious that had caused a malware to be installed on the system. Since Emma's computer was connected to the network, the malware had traveled to the server and two other computers in the day care center. Suddenly the video capabilities of the center went down, causing panic - this was obviously not a good situation!

The administration realized they needed a way to prevent this from happening again. Matt suggested installing a Cisco ASA 5505 that was introduced in 2005 and had a good track record of providing firewall and intrusion prevention. In this case, if there was a well configured firewall, when Emma clicked the link, the firewall would have blocked the malicious site from loading and installing viruses and spyware.

Cisco ASA 5505 Installation

Matt placed an order for a Cisco ASA 5505 and was excited to open the package and confirm the contents when it arrived. It contained the main ASA box or chassis which had 7 ethernet ports, a power supply adapter, a console cable, a power cable and a quick start guide.

A quick review of the current connection showed that the ethernet cable was connected directly from the ethernet port on the wall to the desktop computer that Emma was working on. This allowed Emma to be able to connect to the world wide web and browse internet sites. The first step that Matt had to do was to connect the ASA device so that all network traffic would pass through the device.

On the ASA device the first Ethernet port is Port 0 and is the outside port that allows for public network or internet access. Matt first connected the ethernet cable from the ethernet port on the wall to Port 0 to allow for outside network access. For now, Matt used the default connection for the switch port 0/0 which is the outside port, he might decide to change the port assignments sometime later. He then connected one end of the power cable to the power supply adapter and the other end of the power cable to the electrical outlet on the wall so ASA device could now be powered. One thing Matt noticed was that the ASA device did not have a power switch, so as soon as he connected the power cable to the electrical outlet on the wall, the LED on the device turned a solid green indicating the device was now powered.

How Cisco ASA 5505 Works

The day care center had a server, 3 computers and a networked printer. Matt connected the ethernet cables for each of the computers, servers and the printer to one of the ports numbered 1 through 7 on the ASA device. These ports are also known as inside ports since they allow for network traffic to travel inside the center's network from one device to another.

When Emma saves a document to the server, the data travels from Emma's computer to the server through the ASA device. If the ASA device is configured properly it will identify files that are executable and may contain potential virus or malware and not allow for these files to be saved on the server. Also, when Emma browses the internet now, the ASA device acts as a guard between her computer and the outside network, blocking any unusual activity and sites that can be potentially dangerous.

Initial Configurations

Matt then accessed the graphical interface for the ASA device, also known as ASDM or Adaptive Security Device Management. This is a software that talks to the device using the default IP address for connecting to the ASA device on the internet. The very first thing he did was to configure the login credentials for the administrator interface. He then proceeded to run the startup wizard and followed the required steps that allowed him to modify and customize security policies to match the deployment needs of the day care center.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account