Based on this we have to do something about it. From what I see there are several ways to fix this:
- F5/BigIP as reverse Proxy, well it's not cheep but can fix this.
- ISS WAP, well you need to setup ADFS and this takes some time, and time is Money :-)
- ISS ARR, it's good for Lync 2013 and Exchange but be aware of server OS Version, ISS ARR Version, or you will not get it to work. I used Windows 2012 (NOT R2) and ISS ARR 3.0, and it worked for Lync 2013.
- KEMP, it's not for free but it easy to install, easy to work and you can it running as VLM. The smallest one cost about 1600 EUR inkl 1| year basic support.
So from my view I think it's time for you who has Forefront TMG 2010 to start to plan for the future.