Yesterday there was a chat on Twitter about the usage of IP-Range vs. AD-Site based boundaries for System Center Configuration Manager 2012 SP1.
There is an easy way to get the best of both worlds. It relies on the proper configuration of IP-Subnets in the Active Directory Site Configuration (well, that should be configured properly anyway!)
If you have your subnets configured, then switch to the SCCM Console to Administration, Hierarchy Configuration, Discovery Methods and open the Properties of the “Active Directory Forest Discovery”
Here you can enable “Automatically create IP address range boundaries for IP subnets when they are discovered”
To keep the boundaries up to date, you can even run this discovery on a schedule.
When the discovery is run, you will find the IP-Ranges in your boundaries
You can then select all IP-Ranges of one site and put them into a boundary group by right clicking the selected IP-Ranges.
Hope it helps someone.