DHCP Server not functioning - disable RPC filter in ISA

I found a weird situation on one of my SBS servers where DHCP wasn't working. When I went into the DHCP management console, I saw this:





After some investigation, I had to disable this RPC filter in the ISA firewall. Of the 9 SBS boxes I manage that all serve DHCP, this is the only box I've ever had to do this with. So weird. Here is the RPC filter in application filters I had to disable:

Implementing a Change Password button in OWA

http://www.petri.co.il/enable_password_changing_through_owa_in_exchange_2003.htm

and if you have ISA:

http://forums.techarena.in/showthread.php/showthread.php?t=442474

which says The change password functionality uses a different URL, and there's no ISA
Rule that covers granting access to it, ergo ISA says "403 Forbidden" and
blocks it.

You need to add /iisadmpwd/* to the OWA Web Publishing Rule in the paths
tab, using the same format as the existing entries.