Question 916 of 952 from exam 200-125: Cisco Certified Network Associate Exam
Question
A corporation wants to add security to its network. The requirements are:
-Host C shoulb be able to use a web browser(HTTP)to access the Finance Web Server
-Other types of access from host C to the Finance Web Server should be blocked.-
-All acces from hosts in the Core or local LAN to the Finance Web Server should be blocked
-All hosts in the Core and local LAN should be able to acces the Plublic Web Server.
The task is to create and apply a numberd acces list with no more three statements
Access to the Router CLI can be gained by clicking on the appropriate host.
All passwords have been temporarily set to "cisco".
The Core connection uses an IP address of 198.18.196.65
The computers in the Hosts LAN have been assigned addresses of 192.168.33.1 192.168.33.254
Host A 192.168.33.1 -
Host B 192.168.33.2 -
Host C 192.168.33.3 -
Host D 192.168.33.4 -
The servers in the Server LAN have been assigned addresses of 172.22.242.17 172.22.242.30
The Finance Web Server is assigned an IP address of 172.22.242.23.
The Public Web Server is assigned an IP address of 172.22.242.17
Answers
Explanations
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A.A
Click the console PC and enter the following commands.
Corp1>enable -
Password: cisco -
We should create an access-list and apply it to the interface which is connected to the Server LAN because it can filter out traffic from both Sw-Hosts and
Core networks. The Server LAN network has been assigned addresses of 172.22.242.17 - 172.22.242.30 so we can guess the interface connected to them has an IP address of 172.22.242.30 (.30 is the number shown in the figure). Use the "show ipint brief" command to check which interface has the IP address of 172.22.242.30.
Corp1# show ip int brief -
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 192.168.33.254 YES manual up up
FastEthernet0/1 172.22.242.30 YES manual up up
Serial0/0 198.18.196.65 YES manual up up
We learn that interface FastEthernet0/1 is the interface connected to Server LAN network. It is the interface we will apply our access-list (for outbound direction)
Corp1# configure terminal -
Our access-list needs to allow host C - 192.168.33.3 to the Finance Web Server 172.22.242.23 via web (port 80)
Corp1(config)# access-list 100 permit tcp host 192.168.33.3 host 172.22.242.23 eq 80
Deny other hosts access to the Finance Web Server via web
Corp1(config)# access-list 100 deny ip any host 172.22.242.23
All other traffic is permitted -
Corp1(config)# access-list 100 permitip any any
Apply this access-list to Fa0/1 interface (outbound direction)
Corp1(config)# int fa0/1 -
Corp1(config-if)# ip access-group 100 out
Corp1(config-if)# end -
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 the Core network.
Click on host C and open its web browser. In the address box type http://172.22.242.23 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 can't access Finance Web Server from these hosts.
Finally, save the configuration -
Corp1# copy run start -
Destination filename [startup-config]?
Building configuration...
[OK]
Corp1#
