Our web server (win 2008 R2 with IIS 7.5) had these issues on the SSL Server Test:
Downgrade attack prevention: No, TLS_FALLBACK_SCSV not supported
Uses common DH primes: Yes, Replace with custom DH parameters if possible
DH public server param (Ys) reuse: Yes
Are these things I should truly be concerned about, and if so what are some options I have to deal with them?