I have requirement to allow users to access all blogs over internet but at the same time users should not able to post or reply on blog pages.
Can this be achieved using MWG?
In the request cycle, Command.Name equals "POST" is the condition you want to key on.
You still need to do rule tracing and/or HTML review to find what URL's the POST will be made to.
And, note that this may not be how that blog works, so you might have to do a bit of reverse engineering.