Troubleshooting ipconfig

Resolutions: 1) If this is XP, obtain the latest service pack for Windows XP.
2) Use the Network Diagnostics tool to identify any failed settings. To do this, go to Help and Support>Use Tools to view your computer information and diagnose problems>Network Diagnostics>Scan your system. When the process finishes, check for any items marked "FAILED" in red, expand those categories, and view the additional details about what the testing showed.
3) Assign a static ip on the client and ping the DHCP server. If you can't ping the DHCP server, check the connection and hardware.
4) If you can ping the DHCP after assigning static ip, check the DHCP settings.
5) Make sure no firewall is running on your LAN.
6) Run Repair this connection if it is XP. Or use netsh to reset TCP/IP configuration.
7) If it is win98/w2k, remove and reinstall TCP/IP.
8) Try to upgrade the new NIC driver.
9) Make sure you don't run out of IPs in the DHCP scope.
10) If you use a router as DHCP, you may want to upgrade the firmware.

Cannot use the 2nd NIC

Symptom: You have two computers and each one has two NICs. You are using the first NIC with 192.168.1.0/24 to connect the Internet and it works. You also want to use the 2nd NIC with crossover cable to connect to each other using the same IP range (one is 192.168.1.10 and another is 192.168.1.11). You can't ping each other (192.168.1.10 and 192.168.1.11).

Resolution: The 2nd NICs should use the different IP range.

IP address conflicts

SYMPTOMS: when trying to set the IP address on a NIC, you may receive the following error message: "The IP address `XXX.XXX.XXX.XXX` you have entered for this network adapter is already assigned to another adapter `Name of adapter`. `Name of adapter` is hidden from the network and Dial-up Connections folder because it is not physically in the computer or is a legacy adapter that is not working. If the same address is assigned to both adapters and they become active, only one of them will use this address. This may result in incorrect system configuration. Do you want to enter a different IP address for this adapter in the list of IP addresses in the advanced dialog box? "

RESOLUTION:
1. If you click Yes, you see the TCP/IP properties where you can change the IP address. Then assign the different IP.
2. If you click No, the IP address is assigned to the network adapter. To resolve this problem, uninstall the ghosted network adapter from the registry: At command prompt, type `set devmgr_show_nonpresent_devices=1`, and then press ENTER. Type `Start DEVMGMT.MSC`, and then press ENTER. Click View, and then click Show Hidden Devices. Expand the Network Adapters tree and right-click the dimmed network adapter, and then click Uninstall.

No IP while the network cable is disconnected

Symptoms: your computer has a static IP. However, the ipconfig shows no IP (Media State - Cable Disconnected) while the network cable is disconnected.

Cause: this is by design. If you have some software using TCP/IP whiteout connecting to a network, you may setup it manually.

No operation can be performed on the adapter

Symptoms: when attempting to use ipconfig /release or renew command, you get "No operation can be performed on the adapter <xxxxx...> as this connection has its media/cable disconnected.

Causes: 1. The network is up-plugged or no NIC. 2. You are using static IP.

One-way ping only

If you can ping other computers and other computers can't ping your computer, this is often caused by an improperly configured firewall
on you computer. For example, ICF should not be enabled on LAN NIC.

Symptoms: In your domain network, some computers (most are win9x) obtain mask 255.255.255.0 instead of 255.0.0.0 randomly and they can't logon to the Domain. IPCONFIG /renew doesn't fix the problem. If you assign static ip and correct mask, the computer will be able to logon without any problem. If you check the WINS, you may find many bad records.

Possible reasons: you may have another network device (possible a router) except main DHCP functions as a DHCP.

Why do I get 169.254.x.x IP?

Symptom: The Internet Assigned Numbers Authority (IANA) has reserved 169.254.0.0-169.254.255.255 for Automatic Private IP Addressing. If the computer can't get ip from DHCP, APIPA provides an address that is guaranteed not to conflict with routable addresses.

Resolutions: 1) Make sure you have good connection.
2) Check the hardware and settings.
3) Make sure the DHCP is working.
4) For the test, you can assign static ip. If static ip works, it is possible DHCP issue. If static ip doesn't work, check the hardware or connection.
5) WinSock2 stack may be corrupted and need to repair.

Question: I have assigned a static ip, subnet to the computer, but the ipconfig shows IP address is 0.0.0.0 and subnet mask 0.0.0.0.. Why?

Answer: An existing IP address on the network has the same IP address. You may use tracert ip, WINS and DNS records to find out another computer using the same IP.

If your laptop users frequently disconnect from one network segment and reconnect to another network segment, they may not be able to access the second network. Resolution will be run ipconfig /registerdns.