Bad mask 0XFFFFF

[hfakoor222]

Why does 255.0.0.0 work on this interface yet 0.255.255.255 or 0.0.0.255 does not?

for ip 3.3.3.1 

This is a standard interface configuration command applied on a freshly booted router. I spent last week figuring out how to manually do prefixes so I wouldn't have to use a CIDR chart, yet this eludes me

[balaji.bandi]

As per the standards and Coding what to accept as ip address was pre-defined, so the IP address format will be used all over the same IP and subnet mask (not inverse mask) - inverse mask use only in the access list.

you can find some information below :

https://www.cisco.com/en/US/docs/ios/11_0/access/configuration/guide/acip.html#wp1148

https://www.cisco.com/c/en/us/support/docs/security/ios-firewall/23602-confaccesslists.html

[Flavio Miranda · Accepted solution]

The notation 0.255.255.255 is known as Wildcard mask and have specific utilization in ACLs and Routing protocols.  When configuring an interface, the first bits represent the network and the last the host...probably by using Zero on the begining means that you are igoring the network part. 

 A full and boring explanation you may find on the RFC 1122.

https://www.rfc-editor.org/rfc/rfc1122