Section 23 – Review 8

Section 23 Tasks

• Take the exam below
• Review any theory (if required) or NAT
• Complete the challenge lab below
• Read the ICND1 cram guide
• Spend 15 minutes on the subnetting.org website

Section 23 Exam

1. Write down the commands to configure a DHCP pool on a router for network addresses 172.16.1.0 to 10. Exclude one of the addresses. Add a lease of two days and a DNS IP address.
2. Which command will turn off CDP for the entire router? Which command will turn off CDP for the interface only?
3. Convert 192.160.210.177 into binary (without using a calculator).
4. Convert 10010011 into decimal.
5. What is the private range of IP addresses?
6. Write out the subnet mask from CIDR /20.
7. Write out the subnet mask from CIDR /13.
8. 192.168.1.128/26 gives you how many available addresses?
9. What is the last host of the 172.16.96.0/19 network?
10. Starting with 192.168.1.0/24, with VLSM you can use a /26 mask and generate which subnets?

Section 23 Answers

1. ip dhcp excluded-address 172.16.1.11 172.16.1.255
   ip dhcp pool CCNA
   network 172.16.0.0 255.255.0.0
   dns-server 8.8.8.8
   lease 2

2. The no cdp run command turns off CDP for the entire router and the no cdp enable
   command turns off CDP on the interface only.
3. 11000000.10100000.11010010.10110001.
4. 147.
5. 10.x.x.x – any address starting with a 10
   172.16.x.x to 172.31.x.x – any address starting with 172.16 to 172.31, inclusive
   192.168.x.x – any address starting with 192.168
6. 255.255.240.0.
7. 255.248.0.0.
8. 62.
9. 172.16.127.254.
10. 192.168.1.0.0/26, 192.168.1.0.64/26, 192.168.1.0.128/26, and 192.168.1.0.192/26.

Section 23 Lab – Multi-technology

Topology

Instructions

Connect three routers together with Serial or Ethernet connections. We are using RIP for convenience, although it isn’t tested in the exam:

1. Configure the connections between the routers and ping
2. Add Loopback addresses to the three routers, as per the diagram
3. Put 172.16.1.0/30 and 10.1.1.0/20 and both 192 networks into RIPv2
4. Add a static route on the two spoke routers for network 192.168.20.0/24 to go to the hub
5. Configure a NAT pool on the hub router for network 172.20.1.0/29 to perform NAT to
   pool 192.168.20.0/24
6. Check to ensure that all RIP routes are in the routing table with their correct networks
7. Source a ping from 172.20.1.1 to the Loopback addresses on the spoke routers; turn on a
   NAT debug first and check the NAT table afterwards

Solution Hints and Commands

• router rip
  no auto
  ver 2
  network x.x.x.x
• Static route: ip route command
• ip nat pool <name> <start_ip> <end_ip> netmask <mask> command
• ip nat inside source list x pool <name> command
• show ip route command to check the networks in the routing table
• debug ip nat [detailed] command