Shared Server Duplicate IP Address – Solved

System Administrators can occasionally come across instances where your main file or sql sever fails to connect to the network due to an invalid address.

Troubleshooting the basics:

– Run ipconfig via CMD (command line) on current server. This will show current IP address of server or host machine.

If the first octet is 169. you have an IP conflict. A beginning 169 IP octet is the first clue to an addressing problem.

1. If ipconfig command results in correct IP – restart the server and issue will be resolved.

2. If ipconfig produces a 169. first octet IP address, follow below instructions:

A 169 address is an automatic address assigned by Microsoft if no available addresses are assigned to a network card (NIC).

Possible Causes:

1. Was Server or Host assigned a static IP address that was reserved? More about IP reservations here.

2. Was a legacy device plugged in? This is more common than you might think! Think back to what was changed before this issue occurred including telecomm and networking work not done by you.

3. Find the MAC address of the IP address in conflict with Server or host.

Run the command arp -a

find the IP address in conflict with MAC address

– Download a network scanner that will discover devices based off IP and MAC address

– Find device by Manufacturer, Device Type, Ect.

Once you have found conflicting device, shutdown network port or turn off device.

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