Audain.net ACL lab
Cisco IOS Technologies

ACL Cisco Exam lab 2017

A corporation wants to add security to its network. The requirements are:

  • Host C should be able to use a web browser (HTTP) to access the Finance Web Server.
  • Other types of access from host C to Finance Web Server should be blocked.
  • All access from host in the Core or local LAN to Finance Web Server should be blocked
  • All hosts in the Core and on local LAN should be able to access the Public Web Server.

You have been tasked to create and apply a numbered access list to a single outbound interface. This access list can contain no more than three statements that meet these requirements.

Access to the router CLI can be gained by clickng on the appropriate host.

All passwords have been temporarily set to “cisco”
The Core connection uses an IP address of 198.18.209.65
The computers in the Hosts LAN have been assigned addresses of 192.168.78.1 – 192.168.78.254

  • host A 192.168.78.1
  • host B 192.168.78.2
  • host C 192.168.78.3
  • host D 192.168.78.4

The Finance Web Server has been assigned an address of 172.22.146.17.
The Public Web Server in the Server LAN has been assigned an address of 172.22.146.18

Step 1: select the console on Corp1 router:

Step 2: configuring ACL on Corp1 router:
Password: cisco
Corp1>enable
Password: cisco
Corp1#configure terminal
Corp1(config)#

First command: allow host C (192.168125.3) to the Finance Web Server 172.22.109.17 via HTTP (port 80):

Corp1(config)# access-list 100 permit tcp host 192.168.125.3 host 172.22.109.17 eq 80

Second command: blocking all other access to the finance web server:

Corp1(config)#access-list 100 deny ip any host 172.22.109.17

Third command: allow all hosts in the Core and on the local LAN access to the Public Web Server (172.22.109.18):

Corp1(config)#access-list 100 permit ip any host 172.22.109.18

Step 3:

Apply this access-list to Fa0/1 interface (outbound direction):

Notice: We have to apply the access-list to Fa0/1 interface (not Fa0/0 interface) so that the access-list can filter traffic coming from both the LAN and the Core networks.

Corp1(config)#interface fa0/1
Corp1(config-if)#ip access-group 100 out

Audain.net ACL lab

Step 4:

To verify, just click on host C to open its web browser. In the address box type http://172.22.109.17 to check if you are allowed to access Finance Web Server or not. If your configuration is correct then you can access it. Click on other hosts (A, B and D) and check to make sure you cannot access Finance Web Server from these hosts. Then, repeat to make sure they can reach the public server at 172.22.109.18.

Step 5:

Finally, save the configuration

Corp1(config-if)#end

Corp1#copy running-config startup-config