IPcalc and Wildcard Bits

Submitted by reuben on Mon, 20/02/2006 - 23:30

As a Network Engineer, I occasionally find myself trying to figure out reverse wildcard bits for Cisco router access lists.  For some reason Cisco use these reverse wildcards instead of normal ones in ACLs.

That's fine, except I can never work them out in my head as I know the most basic ones by heart, the slightly less basic ones I can calculate in my head, but the tricky ones are a bit hard going.

Well tonight I did need to work one out (for Microsoft, 65.52.0.0/14) and so found a tool to do it, and posted it up on my website so that it runs on my server for anyone to access.

Go to http://ipcalc.reub.net/ and check it out. It's very simple but does the job wonderfully.

Btw, 65.52.0.0/14 is also represented as 65.52.0.0 0.3.255.255 which is what I was looking for ;-)