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New Member

invalid mask?

I am configuring a Supervisor 2T with the vlan interface 255.255.255..192

and it is giving me the error "bad mask" (won't accept)

ip classless is enable, and ip subnet-zero is a default yes?

Why isn't it taking that network? isn't it valid? ( - 63 /26)

Hall of Fame Super Gold

invalid mask?

Maybe it's overlapping something already there.

Can you post the output to the command "sh run | i 192.168".

New Member

Re: invalid mask?

If the same subnet is being used on another interface you will get a different message
Are you sure this is not because of a typo? I see there are two dots in "..192"

Sent from Cisco Technical Support iPhone App

New Member

invalid mask?

above was a typo: it is

I will check on Monday to see if it is overlapping: really weird that I am getting this

Re: invalid mask?

Hello Colin,

pleae refer to the below:

network address is:

first host is : 192.168.94. 1

last host is :

Subnet mask is :

your host range is from (1 to 62)  the next IP address is broadcast address. by then you cannot assign this ip address to your hosts.

briefly you have assign from ( to

this is correct, if this is an interface of a router, but if you have a MLS; befor you assign any IP aadress you have to apply CLI (no switchport).


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invalid mask?

Please provide the following -

show version

show module

configuration that you do in the interface mode along with the error message you get

Hall of Fame Super Silver

invalid mask?

I agree that the error bad mask is not the result of overlapping addresses. It typically caused by attempting to use the subnet address, the broadcast address, subnet zero not enabled, or perhaps some typo in the address.

I would like to see the output of show ip interface for the interface in question. I think that the output of show ip protocol might also be helpful.