Hello everyone, I am reading the Cisco 5.2.3 ACL WIldcard Masking chapter and I have come across a stump....something that I cannot get myself to understand.
With the image that I've attached, you will see that cisco is using the 192.168.10.0 IP and a wildcard mask of 0.0.255.255. I am guessing it's safe to say that with the inverse mask being 0.0.255.255, that the subnet would be 255.255.0.0 thus being a /16 subnet.
My problem is understanding why Cisco choose to use 0.0.255.255 for 192.168.10.0. Why didn't they use 0.0.0.255?
From what I can see from the image it shows an IP address of 192.168.10.0 which is a valid IP address with the mask of a /16(255.255.0.0). It would not be a valid IP address if it was a /24(255.255.255.0) since that would be a host address which is the reason for the 0.0.255.255 wild card mask they choose to show. Hope this helps.
I'm not sure how familiar you are with subnetting but I'll try to make this hopefully easy to follow...
So for 192.168.10.0 with a /16(255.255.0.0) mask you would have a valid IP range of..
so 192.168.10.0 would fall within that range of usuable.
For 192.168.10.0 with a /24(255.255.255.0) mask you would have a valid range of..
So from the above example you can see that 192.168.10.0 would not be a valid ip address with a /24. If it was 192.168.10.1 then it would be and then the picture you posted before might show the wildcard mask as 0.0.0.255.
We are pleased to announce availability of Beta software for 16.6.3.
16.6.3 will be the second rebuild on the 16.6 release train targeted
towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are
looking for early feedback from customers befor...
Introduction Featured Speakers Luis Espejel is the Telecommunications
Manager of IENova, an Oil & Gas company. Currently he works with Cisco
IOS® and Cisco IOS XE platforms, and NX to some extent. He has also
worked as a Senior Engineer with the Routing P...
In this session you can learn more about Layer 3 multicast and the best
practices to identify possible threats and take security measures. It
provides an overview of basic multicast, the best security practices for
use of this technology, and recommendati...