Cisco Loopback Address Question

Hello Experts,

I'm getting 'bad mask' when I enter the following ip address:

ip address
Bad mask /32 for address

I thought you could add /32 for any address?


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Kash2nd Line EngineerCommented:
Your IP address needs to be which is the only useable address you have.

Broadcast Address:
cpatte7372Author Commented:

I'm assigning the ip address to inteface FastEthernet0/0

Faruk Onder YerliOwnerCommented:
Dear cpaette;

practically you should assign /32 IP address just in loopback interface. Fast or Giga interfaces needs to use min /30 range. IT is meaningless to  use /32 on physical interface.

If you already assign ip address like in physical interface, loopback has to be out of physical range scope. If you are not using vrf function on router, each interface network has to be different eachother.

Good days ..

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Don JohnstonInstructorCommented:
I'm pretty sure that the longest mask you can have on a physical interface is a /31.  I don't remember which IOS version began supporting the /31.  A late 12 or early 15, IIRC.

But no /32's.
cpatte7372Author Commented:
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