Problem-Solving Checklist and Worksheet

To isolate problems in your internetwork, you must first compile all the relevant facts and then methodically address each suspect problem. This appendix provides a troubleshooting checklist and general worksheet to help you in this process. Use the checklist and worksheet as initial guidelines to assist you in developing your own checklist and worksheet--one tailored to your own internetworking environment.

Troubleshooting Checklist

Before you start making any changes to your internetwork, be sure you can answer the following questions positively:

1. Have you identified and compiled a list of all the reported symptoms on your internetwork?
   
   
2. Do you know your internetwork? Do you have an accurate physical and logical map of your internetwork?
   
   
3. Do you have a list of all the network protocols implemented in your network?
   
   
4. Do you know which protocols are being routed?
   
   
5. Do you know which protocols are being bridged?
   
   
6. Do you know all the points of contact to external networks?
   
   
7. Do you know all the internetwork equipment in your network?
   
   
8. Have you identified an end system or internetwork node that might be the cause of a problem?
   
   
9. Do you know the applications that are being used in your network?
   
   
10. For every symptom, have you developed a list of potential problems and causes?
    
    
11. For each problem, do you have a plan of action?
    

If you can answer yes to these questions, you can begin the process of isolating problems. Remember to eliminate one problem at a time.

Troubleshooting Worksheet

.	Symptoms reported:

.	Network topology map--attach separate sheet(s)

.	Network protocols implemented:

.	Protocols routed:

.	Protocols bridged:

.	Points of contact to external networks:

.	Internetwork equipment (including network address, vendor, model, and function):

.	Suspect end system and internetwork nodes (including network address, vendor, model, and function):

.	Applications being used on the network (FTP, sendmail, NFS, NetWare, and so forth):

.	Symptoms and possible problems:

Symptom		Possible Problems

.	Action plan for each problem:

Problem		Action Plan

.	Action outcomes:

Problem/Action		Result/Outcome