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JBrav0
Beginner

Is it bad practice to give a switch port a static IP address?

Normally I would give the a device that always needs to be on a static IP address through its web interface or command line. 

However I ran into a different device. Its a security panel that's always on and there is no way to log into it, no web interface. Nothing. In a week we plan to swap it out for a newer version. An I was thinking of setting that IP address that it currently has under the switch port that its hooked up to. That way when we swap it out it just takes the same IP address. I just cant remember if that's good practice and if it does that where the device takes over the IP address in the port. 

1 ACCEPTED SOLUTION

Accepted Solutions
RFS
Beginner
Beginner

Cisco switches generally don't have IP addresses assigned to Layer 2 access ports. A Layer 3 port doing routing would have an IP address assigned to it. If one device is connected to the port it is usually an access port with no IP address so the security panel most likely is assigned the IP address. When you change out the security panel note the IP address you think is assigned to the port/device, and after removing the panel, shutdown the port, and ping the IP address. If you get a response there is another device on the network with the same IP address. You need to select a different IP or resolve the IP address conflict with the other device before installing the new security panel.

When you add the new security panel assign the IP address to the panel. The Layer 2 port shouldn't have an IP address.

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4 REPLIES 4
Jon Marshall
Hall of Fame Guru

 

Not sure I follow. 

 

If the switch is a L3 switch you can configure an IP on a port but a device attached to that port won't take the IP. 

 

Jon

I didnt know that, then what is the point of being able to assign IP addresses to switch ports? 

 

Used primarily as a L2 boundary ie. if you wanted to uplink to a router you could configure the port on the switch as L3 and assign an IP directly to it so it would not run STP etc, across the link to the router. 

 

Jon

RFS
Beginner
Beginner

Cisco switches generally don't have IP addresses assigned to Layer 2 access ports. A Layer 3 port doing routing would have an IP address assigned to it. If one device is connected to the port it is usually an access port with no IP address so the security panel most likely is assigned the IP address. When you change out the security panel note the IP address you think is assigned to the port/device, and after removing the panel, shutdown the port, and ping the IP address. If you get a response there is another device on the network with the same IP address. You need to select a different IP or resolve the IP address conflict with the other device before installing the new security panel.

When you add the new security panel assign the IP address to the panel. The Layer 2 port shouldn't have an IP address.

View solution in original post