Palo Alto RADIUS authentication against Microsoft NPS is broken

L2 Linker

Recreating the RADIUS server profile did the trick. (actually, changed the timeout and retry from 3 to 2 and pushed from panorama). The system log now says it switched to PAP for that radius server.


That's a nasty bug... Never would have tought 'touching' the radius config could fix the issue...

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L2 Linker

Found this issue on another firewall (Panorama 7.0.2) - I could also resolve it by modifying the RADIUS configuration. Great find!

L2 Linker

Woop woop.. From the PAN-OS 7.0.4 release notes:


Added a new CLI operational command ( set authentication radius-auth-type <auto|chap|pap> ) to address an incompatibility issue between PAN-OS and some RADIUS servers. With this fix, you can manually override the automatic selection mechanism introduced with Challenge-Handshake Authentication Protocol (CHAP) support in PAN-OS 7.0 to select either CHAP or Password Authentication Protocol (PAP) as needed.


TLDR; CLI command set authentication radius-auth-type <auto|chap|pap>

L3 Networker

Thank you. But, it looks like it can be done only via CLI, how about configuring CHAP from GUI? 

L3 Networker

Well, even from the CLI, it doesn't seem to take the command. 

rbista@MyFirewall> configure
Entering configuration mode
rbista@MyFirewall# set authentication radius-auth-type chap

Invalid syntax.


Any suggestions? I ran the command # find command keyword "radius-auth-type", it display the command though. 

rbista@MyFirewall> find command keyword "radius-auth-type"
set authentication radius-auth-type <auto|chap|pap>

L5 Sessionator

What is the PAN-OS on the firewall?

L5 Sessionator

It will work on PAN-OS 7.0.4. You dont have to go in configure mode.


admin@fw63> set authentication radius-auth-type chap


Hope this helps!


Merry Christmas :)

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