On Fri, Feb 18, 2011 at 03:02:49PM +0000, Dean, Barry wrote:
On 18 Feb 2011, at 14:26, Phil Mayers wrote:
On 18/02/11 14:16, Dean, Barry wrote:
I have been asked to do just this and I am working on the solution now.
We wanted to use multiple pools of VLANs/Subnets and assign "Staff" to one pool and "Students"# to the other. Then to select a VLAN within the pool, use a hashing function and select a VLAN.
One concern I have is when is post-auth called? Would it get called for interim authentication requests? Because I don't want to be changing the VLAN mid sessions, which could potentially happen with a non-deterministic hash!
There is no such thing as an "interim" authentication request.
Post-auth is called after every auth.
I suspect you are referring to feature(s) on the switch(es) you use where it will "re-auth" the client after X minutes. That's just another, separate authentication as far as FreeRadius is concerned
Yep, I was referring to the entries I see in my logs for "Interim-Update", which is of course an Accounting record, and I had always assumed this went with an Auth as well, but have never looked in detail to see! So I am most likely talking rubbish!
In my tests I have been creating a hash from the 'State' attribute
That's a very bad idea. It will change mid-session and cause you huge problems.
I will not be using this then :-)
We do pervasive VLAN assignment on a large scale here, and my advice is the same as others in the thread - don't use a hash value. Just map a user or group to a vlan.
If you need to "balance the numbers of users on a vlan" (why?) then you should log the vlan assignments to SQL and run a post-processing script that changes the assignment to keep the "load balanced".
Personally we just run big subnets to reduce the waste of IP space and configuration overhead.
I don't design the wireless network here, I just make the RADIUS work as best I can. It has been decided to have smaller private IP ranges each associated with a VLAN and balance the routing of these across two routers. Then I was asked if I can distribute the users across these VLANS evenly.
This was the initial request from our network group as well.
I am beginning to think a round robin allocation might just do!
That is what they asked for, but the key is to provide a persistent VLAN allocation for the length of the client's connection to the network. You can either cache the current VLAN assignment from a pure round-robin allocation which requires managing the information, expiring it as needed and other sorts of maintenance activities. In the end, using the hash of a static client parameter such as User-Name or MAC address gives you an even distribution without the maintenance headaches. Cheers, Ken
However, the goal posts could move again yet! Latest news is that we will have 1 pool of VLANs, so time to tear up the existing code and take a fresh look! I currently have no idea how big these subnets will be either.
---------------------- Barry Dean Principal Programmer/Analyst Networks Group Computing Services Department Tel: 0151 795 9540 Skype: barryvdean
Content-Description: ATT00001.txt
--- Nice boy, but about as sharp as a sack of wet mice. -- Foghorn Leghorn
- List info/subscribe/unsubscribe? See http://www.freeradius.org/list/users.html