Lab 5.5.6: ISDN Interesting Traffic

Objectives:

  • Place an extended ACL for controlling DDR.

Scenario:

The Denver office needs to control what interesting traffic will bring up the ISDN connection to the Phoenix office. You will setup an extended ACL and apply it to the dialer group.

Notes: 

Lab Tasks:

  1. Use the configurations from Lab 5.5.5. Log into the Denver office router and enter global configuration mode.
  2. You must block all broadcast traffic, ICMP traffic, and all FTP traffic from initiating a call. The commands to setup the access-list are:

    Denver(config)#access-list 100 deny ip any host 255.255.255.255
    Denver(config)#access-list 100 deny icmp any any
    Denver(config)#access-list 100 deny tcp any any eq ftp
    Denver(config)#access-list 100 permit ip any any

  3. The next step will be to apply the access list to the dialer. The command to do this is:

Denver(config)# dialer-list 1 protocol ip list 100

  1. To test the dialer ACL issue the following command:

Denver# ping phoenix

Record your results below:

  1. To again test the dialer ACL issue the following command:

Denver# telnet phoenix

Record your results below:

  1. Exit from the Phoenix router and issue the following command to see how many packets have matched the access-list. The command to view the number of matches to an ACL is:

Denver# show access-list

Record your results below:

  1. The final part of the lab is to issue the following command while the BRI interface is up:

Denver# ping phoenix

Record your results below:

  1. Why is a ping successful once the dialer is up?