1. Troubleshooting ip
Chapter 5e

2. objectives Upon completion of this chapter, you should be able to:
Find IP configuration settings on Windows & Linux
Troubleshoot IP configuration problems
Use the ipconfig command prompt command
Tell if a host is using APIPA
Identify the difference between netstat and nbtstat
Use the tracert command to find problesm in routing

3. Troubleshooting ip configuration issues
5.8.1
Troubleshooting ip configuration issues

4. What’s wrong here?
is on a different network than the rest.

5. What’s wrong here?
Nothing. This is a Class A. The 3 host octets can be anything with a default SM.

6. What’s wrong here? WE ARE USING SUBNET-ZERO (THE FIRST TOTAL RANGE)
Magic # in 3rd octet is: 4
Ranges: 2)
Therefore, /22 is in a different range than the rest.

7. What’s wrong here?
Host A is connected to the LAN, but it can’t get access to the Internet. What’s the problem?
/27 (.224)= ; magic # is 32.
Ranges: 32-63, 64-95, etc.
The host & the DG are in different subnets.

8. What’s wrong here?
You can’t ping but you can ping an IP address.
DNS couldn’t translate the name to the IP address.
What should you check?

9. What’s wrong here? APIPA.
The hosts can communicate with each other but not the file server nor the Internet/any other network.

10. Rouge dhcp server Common situations:
Install a server OS on virtual machine for testing & you accidently activate DHCP
Mobile hotspot enabled on phone & DHCP server is enabled on it
Some hosts may get an IP from the rouge DHCP server & not be able to communicate

11. 5.8.2
Using ipconfig

12. Viewing ip info

13. Viewing ip info with ipconfig
IP address, SM DG
Ipconfig /all
Lots more

14. Statically assign ip

15. Let it go… and get a new one
Ipconfig /release
Let’s go of a DHCP assigned address
Ipconfig /renew
Gets a new IP address from DHCP

16. Review- q

17. Using ifconfig on linux
5.8.3
Using ifconfig on linux

18. ifconfig Works pretty much like ipconfig but on Linux
As a standard user, you can view IP info
As a super user, you can modify the IP info
Review TestOut 5.8.3

19. activity TestOut Lab 5.8.5- Explore IP Configuration
TestOut Lab Troubleshoot IP Configuration Problems 1
TestOut Lab Troubleshoot IP Configuration Problems 2
TestOut Lab Troubleshoot IP Configuration Problems 3
TestOut Lab Troubleshoot IP Configuration Problems 4
TestOut Practice Questions (5)

20. Troubleshooting ip communications
5.9
Troubleshooting ip communications

21. Use ping to test Tests connectivity Echo request/echo reply
Can’t get to a website? Try and ping it.
Success= site is up/DNS problem
Fail= other problem/site down
Echo request/echo reply
Try ping destination first, then close to far

22. Use tracert to test Shows the path the packet takes
Can identify exactly where problem is
Windows- tracert
Linux- traceroute
Measures hops (going through a router)
Any * timed out * may mean the router ignores the ICMP traceroute traffic
Example Next Slide

23. Tracert example

24. Arp test Views ARP table (IP-MAC) Arp –a
Arp –d (in administrator mode) allows you to manually remove an entry
Arp –s allows you to manually input an entry

25. netstat
Displays detailed info about how your computer is communicating with other computers or network devices
Info/statistics about the network interfaces, active connections, ports, etc.
Netstat, netstat –a
Netstat: displays only a list of ACTIVE connections
Netstat –a: list of ALL connections AND ports listening (Good for seeing open ports, possibly some rogue stuff coming in)
If you maintain a web server, for example, and it seems to be slow to respond, you could run a netstat to see the established connections, ports being used, traffic stats, etc.

26. activity 5.9.1- Network Communication Troubleshooting
Using Ping & Tracert
5.9.4/ Using arp, netstat
LAB
Practice Questions

27. Troubleshooting name resolution
5.10
Troubleshooting name resolution

28. activity 5.10.1- Name Resolution Troubleshooting
Fact Sheet (Review)
Using nslookup
LAB
Practice Questions

29. Troubleshooting ip
Chapter 5e