Lab Report: 5.8.5 Explore IP Configuration

5. Using tracert 65.86.1.1 verifies a path to the ISP through our default gateway.
6. In the Executive Office, the link and network activity lights on the back of the workstation are on and blinking, indicating that there is a physical connection to the switch and there is activity on the connection. This points to a TCP/IP configuration problem.
7. On the Executive Office workstation (Exec), the network icon in the notification area has a yellow warning sign with an exclamation point which indicates a connection to the local network, but no access to the Internet. When you click the network icon, you see the details of this status. The Network and Sharing Center diagram confirms that Exec is connected to the local network, but has no Internet access.
8. On Exec, you are able to ping the local interface on Exec by name (since you don't know the IP address yet), but you can't ping CorpServer or the ISP. This indicates that Exec has a valid connection, but can't communicate with CorpServer or the ISP.
9. Using ipconfig /all provides the following information about the Local Area Connection on Exec:

DHCP Enabled: No

IPv4 Address: 192.168.0.62

Subnet Mask: 255.255.255.240

Default Gateway: 192.168.0.4

This information provides us with at least two clues to the problem:

1. The network is using DHCP, but this workstation is not enabled for DHCP.
2. Given the workstation's current subnet mask, the IPv4 Address of the workstation and the

Default Gateway are not on the same network. In addition, the subnet mask is not the default

subnet mask for the Class C IP address range being used. With 255.255.255.240 as a subnet mask, the network would only include addresses from 192.168.0.48 to 192.168.0.63. The IP address for CorpServer (192.168.0.10) and the ISP fall outside of this range. The information in step 4 confirms that the default subnet mask for the Class C IP address range (255.255.255.0) is being used.

10. After correcting the subnet mask on Exec, there are still no changes to the network icon or to the diagram in the Network and Sharing Center.
11. After correcting the subnet mask on Exec, you can now ping CorpServer, but you still can't ping the ISP. This indicates that you only have local connectivity.
12. Use tracert 65.86.1.1. The command times out, indicating the following:

The ICMP packets are not returning from the first hop (gateway) in its path to the ISP. Exec is not finding the gateway.

The gateway address on Exec is not configured correctly. (The gateway address (router) on the network diagram is 192.168.0.5.)

13. After configuring the correct gateway address on Exec, the network icon and the diagram in the Network and Sharing Center confirm that Exec is connected to the Internet.
14. Using the tracert command again returns a path to the ISP through the gateway. Since we have a valid connection to the Internet, we will leave the static address for now while we troubleshoot in Office 1.
15. In Office 1, the link and network activity lights on the back of the workstation are on and blinking. Once again, this points to a TCP/IP configuration problem.
16. On Office1, the network icon and the diagram in the Network and Sharing Center indicate that Office1 is connected to the Unidentified network and has no Internet access.
17. You are able to ping the local interface, but you can't ping CorpServer or the ISP. This indicates that Office1 has a valid connection to the local network.
18. Using ipconfig /all provides the following information about the Local Area Connection:

DHCP Enabled: Yes. This tells us that the workstation is configured to use a DHCP server.

IPv4 Address: This address is in the APIPA range (169.254.0.1 to 169.254.255.254). This means that the workstation assigned itself an IP address instead of receiving one from the DHCP server. The workstation will only be able to communicate with other hosts on the local network that have also configured their own IP address through APIPA.

Subnet Mask: 255.255.0.0. This is the default subnet mask for the APIPA address.

Default Gateway: (blank). This means that communication is limited only to other workstations on the local network.

DHCP Server line is not shown. This means that the workstation was unable to contact the DHCP server. DNS Servers line is not shown for IPv4.

Since DHCP is enabled, the rest of the information should have come from the DHCP server. We can conclude that there is an issue with the DHCP server.

19. On CorpDHCP12, launch the DHCP console and activate the scope.
20. On Office1, the ipconfig /renew command will request new IP address information from the DHCP server, and it will reconfigure the settings for the Local Area Connection.
21. The ipconfig /all command will check the Local Area Connection You should notice the line for the default gateway, DNS server, and DHCP server, along with the new IP address which is now within the DHCP scope for the local network.
22. After activating the DHCP server and receiving a valid IP Address, you can now ping CorpServer from Office1, but you still can't ping the ISP.
23. The tracert command times out on Office1, indicating that it can't get to the gateway. As noted above the gateway should be 192.168.0.5.
24. The ipconfig /all command shows the Default Gateway is set to 192.168.0.2, but we know it should be192.168.0.5. Since this address is coming from DHCP, we need to check the DHCP server.
25. On CorpDHCP12, launch the DHCP console and reconfigure the settings for the DHCP scope.
26. On Office1, the ipconfig /renew command will request new IP address information from the DHCP server, andit will reconfigure the settings for the Local Area Connection.
27. Use the ipconfig /all command to check the Local Area Connection configuration. You should notice the linefor the default gateway is now configured correctly.
28. The network icon and the diagram in the Network and Sharing Center indicate that Office1 is connected to thelocal network and the Internet.
29. When you ping the ISP to confirm resolution, the ping succeeds.
30. On Exec, reconfigure the Local Area Connection to use DHCP.
31. The ipconfig /all command now shows the IP address, Default Gateway, DNS Server, DHCP Server that wereprovided by the DHCP server.
32. The network icon and the diagram in the Network and Sharing Center indicate that Exec is connected to thecorporate network with full Internet access.
33. Use tracert 65.86.1.1, which returns a path to the ISP through the gateway. The network is now fullyfunctional and your troubleshooting is complete.