The subnet calculator helps you design networks by taking an IP address and network mask and returning information such as network, broadcast address, and host range.
One of a set of tools we're offering as a way of saying thank you for being a part of the community.
The first location I would look in is,
Configuration
cn-configuration
cn=services
cn=Microsoft Exchange
cn=<your organisation>
cn=Administrative Groups
cn=<your admin group>
cn=Servers
cn=<your server>
cn=information store
cn=<your storage group>
Then right click on the mailbox store/s and choose Properties, security and then remove the deny. Close ADSIEDIT and then wait a few minutes for the change to replicate.
Restart the information store service so that the permission change is read again.
ADSIEDIT WARNING - Think of it like the registry on your computer, only 10 times worse. Once false move and you could be looking at a rebuild of the domain.
If you aren't sure, then don't do it.
Simon.