2. Lab 274 CCNA

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A network associate is adding security to the configuration of the Corp1 router. The user on

host C should be able to use a web browser to access financial information from the

Finance Web Server. No other hosts from the LAN nor the Core should be able to use a

web browser to access this server. Since there are multiple resources for the corporation at

this location including other resources on the Finance Web Server, all other traffic should

be allowed.

The task is to create and apply an access-list with no more than three statements that will

allow ONLY host C web access to the Finance Web Server. No other hosts will have web

access to the Finance Web Server. All other traffic is permitted.

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.

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Answer: Select the console on Corp1 router

Configuring ACL

Corp1>enable

Corp1#configure terminal

comment: To permit only Host C (192.168.33.3){source addr} to access finance server

address (172.22.242.23) {destination addr} on port number 80 (web)

Corp1(config)#access-list 100 permit tcp host 192.168.33.3 host 172.22.242.23 eq 80

comment: To deny any source to access finance server address (172.22.242.23)

{destination addr} on port number 80 (web)

Corp1(config)#access-list 100 deny tcp any host 172.22.242.23 eq 80

comment: To permit ip protocol from any source to access any destination because of the

implicit deny any any statement at the end of ACL.

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

Applying the ACL on the Interface

comment: Check show ip interface brief command to identify the interface type and number

by checking the IP address configured.

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Corp1(config)#interface fa 0/1

If the ip address configured already is incorrect as well as the subnet mask. This should be

corrected in order ACL to work

type this commands at interface mode :

no ip address 192.x.x.x 255.x.x.x (removes incorrect configured ipaddress and subnet

mask)

Configure Correct IP Address and subnet mask:

ip address 172.22.242.30 255.255.255.240 ( range of address specified going to server is

given as 172.22.242.17 - 172.22.242.30 )

Comment: Place the ACL to check for packets going outside the interface towards the

finance web server.

Corp1(config-if)#ip access-group 100 out

Corp1(config-if)#end

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Important: To save your running config to startup before exit.

Corp1#copy running-config startup-config

Verifying the Configuration:

Step1: show ip interface brief command identifies the interface on which to apply access

list.

Step2: Click on each host A, B, C, & D. Host opens a web browser page, Select address

box of the web browser and type the ip address of finance web server (172.22.242.23) to

test whether it permits /deny access to the finance web Server.

Step 3: Only Host C (192.168.33.3) has access to the server. If the other host can also

access then maybe something went wrong in your configuration. Check whether you

configured correctly and in order.

Step 4: If only Host C (192.168.33.3) can access the Finance Web Server you can click on

NEXT button to successfully submit the ACL SIM.