Wildcard mask help...

CompUBug

How do you determine the wildcard mask for a set of criteria you're trying to filter for your hosts? Basically how do you determine wild card masks?

Also this question, can anyone explain this to me?

What would be the proper wildcard mask to permit all odd numbered hosts on the 10.48.0.0/12 network?

1. access-list 1 permit 10.48.0.0 0.15.255.255
2. access-list 1 permit 10.48.0.1 0.15.255.254
3. access-list 1 permit 10.48.0.0 0.15.255.1
4. access-list 1 permit 10.48.0.0 0.0.0.254
5. access-list 1 permit 10.48.0.0 0.0.0.255

2. is correct. All odd-numbered hosts would have the one bit turned on in the last octet. Therefore, you need to check all hosts that have the one bit turned on (set to 1). You do not care about the other host bits. The default wild card mask for a /12 network is 0.0.15.255, but because you want to match only those hosts that have the one bit turned on, you will need a wildcard mask of 0.0.15.255.254 . 1. is incorrect because this would match both even and odd numbered hosts. 3. is incorrect because this would match all hosts from 10.48.0.0 through 10.48.255.0. 4. and 5. are incorrect because they have the wrong wildcard mask

greenerek

Hi wildcard mask is quite easy - You just need subtract
look
http://www.techexams.net/forums/ccna-ccent/59098-point-wildcard-mask.html
and
http://www.dslreports.com/faq/8336

Try read this , than if is still not clear do not hesitate to ask