AD and enforced password policies

Hello all. Happy New Year. I have a requirement to enforce password policies on AD (a tacacs and windows domain). I don't have a great deal of Windows AD knowledge - so a newbie ;-) this is a little off topic, but I thought I'd ask... Specifically, I need to enforce the use of length, special characters, and be able to validate the enforcement of such. Looking at Nfront, Quest, etc..., and wanted to see if anyone out there had thoughts? Thank you.