FLINT HILLS TECHNICAL COLLEGE
Network Troubleshooting Flowchart

START
Windows Workstation Unable to Access a Network Service
Gather Clues
A. Ask Questions.
 i. What were you doing when the problem occurred?
ii. Have there been any recent changes to the network?
B. Have the customer recreate the problem while you watch.
While watching, check for obvious user errors (ID10T errors), such as Caps-Lock being on.
Do other workstations on the LAN have the same problem?
Yes  or  No
        ↓
Restart the affected workstation. Problem solved?
Yes  or  No
        ↓
Is the Link-Light on the NIC lit?
Yes  or  No
↓        
Execute: ipconfig /all
What type of IP address?
No IP address  or  Valid Static or DHCP  or  DHCP starting with 169.254 (APIPA)
↓                        
ping the destination by name. Successful?
Yes  or  No
               ↓
ping the destination by IP address. Successful?
Yes  or  No
               ↓
ping the default gateway’s IP address. Successful?
Yes  or  No
              ↓
Possible Solutions
A. Incorrect IP address or subnet mask. Compare with the settings on another workstation that is working on the LAN.
B. Incorrect, outdated, or misconfigured NIC driver. Verify NIC driver in Device Manager, and don’t forget to check the NIC’s settings, such as connection speed.
C. Malware infection. Scan system for malware infection using anti-malware software such as MalwareBytes.
D. Reset Windows TCP/IP stack using
netsh int ip reset command. Reboot after executing command and reconfigure the NIC’s IP settings.
E. Faulty cable. Test with cable tester or swap cables. Sometimes link-lights lie. Make sure cable is not too long.
F. If Wireless, lost connection to access point. Make sure workstation is close enough to access point. Check for interference. Make sure wireless NIC is configured with correct SSID & passphrase.
G. Faulty NIC. Try a different NIC in the workstation.
H. Bad entry in local routing table. View it using the route print command, and compare it with the routing table on another workstation that is working on the LAN.
When All Else Fails
A. Sniff the network with Wireshark while recreating the problem. See if packets are actually being sent to the correct addresses and if there are any replies.
B. Search the Internet. See if others have had the same problem, and if so, how they solved it.
Problem Solved?
Document Your Solution
FINISHED

Click here for a graphical version of this flowchart.