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
- 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.
- Which command will turn off CDP for the entire router? Which command will turn off CDP for the interface only?
- Convert 18.104.22.168 into binary (without using a calculator).
- Convert 10010011 into decimal.
- What is the private range of IP addresses?
- Write out the subnet mask from CIDR /20.
- Write out the subnet mask from CIDR /13.
- 192.168.1.128/26 gives you how many available addresses?
- What is the last host of the 172.16.96.0/19 network?
- Starting with 192.168.1.0/24, with VLSM you can use a /26 mask and generate which subnets?
Section 23 Answers
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 22.214.171.124 lease 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.
- 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
- 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
Connect three routers together with Serial or Ethernet connections. We are using RIP for convenience, although it isn’t tested in the exam:
- Configure the connections between the routers and ping
- Add Loopback addresses to the three routers, as per the diagram
- Put 172.16.1.0/30 and 10.1.1.0/20 and both 192 networks into RIPv2
- Add a static route on the two spoke routers for network 192.168.20.0/24 to go to the hub
- Configure a NAT pool on the hub router for network 172.20.1.0/29 to perform NAT to
- Check to ensure that all RIP routes are in the routing table with their correct networks
- 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
- 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