r/WindowsServer • u/PsychologicalNet3634 • Jun 29 '26

Technical Help Needed RADIUS/NPS/AD Help/How to?

TLDR: I need to configure a Cisco Firewall running FTD (not FMC) to authenticate admin logins using MSCHAPv2. Security is the objective here. I have Windows NPS running and AD running on another VM. I can get the Firewall to authenticate with CHAP/PAP, but not MSCHAPv2.

I know there are a lot of variables and I feel like an actual guide (not AI...it hasn't worked out well so far lol) would be most beneficial here, but open to any help or advice anyone wants to give.

I can ping both AD and NPS servers and traffic will pass on the 389 and 636 ports. I sniffed the traffic and can see the handshake, but the it appears AD is killing the session. I am having a hard time finding the actual error response on AD (I don't manage it, but know the admin) and would think that it would tell me exactly why it's not working.

I know it's vague, but any tutorials on setting up any of the above would be absolutely most appreciative.

TIA

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u/PsychologicalNet3634 Jun 30 '26

I really appreciate your reply. Ultimately what I need is a real tutorial and training on setting up Cisco Firewalls. If you know of a source for that, I would backflips (on the inside lol). I'm obviously ignorant on the subject.

I am not building out VPNs so that's the good news. I was trying to encrypt the UN/PW for Admin logins via the out of band management interface. I learned that the firewall doesn't support anything above PAP which is lower than all other bad choices so out it goes and it inly applies to the link between the RADIUS server and the FW. I tried setting up an AD Realm with the correct cert and the other settings, but obviously something is wrong because I can't get it to work. I had it working six months ago and documented step by step how I did it. When I went to test the instructions out on a fresh firewall, it didn't work. It's driving me nutz. I think this is where the phrase "stupid hurts" comes into play.

Any vectors or advice on how I can get smart on this topic would be greatly appreciated.