What i have:
I am running a freeradius server fully configured of how i need it to be. Everything works just fine right now.
What i need:
I need the radius to put the devices in a seperate vlan before authentication and to run a vulnerability scan (nessus / openvas etc) on the devices in this vlan to check for software status ( antivirus etc. ) if the device passes the test the authentication should be done normaly. if it fails it should be put into a third ( fourth if you count the unauth-vid ) vlan.
can someone tell me if this is doable in freeradius ?
thanks in advance for your answers
Yes. But this is a very broad question and is dependent on the networking equipment being used. I'll give you an overview of how I'd design such a system.
In general, you'll have an easier time if you can use the same DHCP server/IP range for your NAC and full access VLAN. That means you don't have to signal the higher networking layers in the client that there's been a state change, you can swap out VLANs behind the scenes to change what they can access.
You'd set up a database with an entry for each client. This doesn't have to be pre-populated, it could be populated during the first auth attempt. Part of each client entry would be a status field detailing when they last completed NAC.
You'd also need an accounting database, to store information about where each client is connected to the network.
If the client had never completed NAC checks before, you'd assign the client to the NAC VLAN, and signal your NAC processes to start interrogating it.
FreeRADIUS can act as both a RADIUS and DHCPv4 server, so you'd probably do signal the NAC process from the DHCPv4 side because then you'd know what IP the client received.
Binding the RADIUS and DHCPv4 sides can be done in a couple of ways. The most obvious is MAC, another common way is NAS/Port ID using the accounting table.
Once the NAC checks had completed, you'd have the NAC process write out a receipt in detail file format, and have that read back in by a detail file listener (there are examples of this in sites-available/ in the 'decoupled-accounting' virtual server files). When reading those entries back in, you'd change the state in the database, and send a CoA packet to the switch using information from the accounting database to identify the client. This would flip the VLAN and allow them to the standard set of networking resources.
I know this is very high level, documenting it properly would probably exceed StackOverflow's character limit. If you need more help with this, I suggest you research what I've described above and then start asking the RADIUS related questions on the FreeRADIUS user's mailing list https://freeradius.org/support/.