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New Member

Duplicate ip address when linux server reboot

These are the equipment I have :

Cisco 2950 switch

Compaq Proliant ML 350

- network card NC3163

- O/S installed ( Linux )

I enable port fast and access mode on switch ports. When I reboot the linux server, it will give me duplicate ip address. There is no problem with my compaq workstation even disconnect and plug into other switch port.

If anyone come across these problem, please share with me how you solve the problem.



New Member

Re: Duplicate ip address when linux server reboot

Hi Sam,

We use Portfast when there is a server cluster and the backup needs to come up without waiting for the learning and listening modes of the switch. So there is a single IP configured and the backup uses the same IP when the primary is down. In your case I am not sure if you have more devices connecting to the switch and which might have the same IP and hence the duplicate IP address is shown. If the IP address you are using is Private, try changing the IP of the server and checking if it gives the same message on reload. If it does not then there is another device having the same IP and so you would need to change the IP.

Use PortFast only when connecting a single end station to a Layer 2 access port. Otherwise, you might create a network loop.

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