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802.1x authentication with IP phones?

802.1x authentication with IP phones?

Hi,

I have a setup like so:

Radius client authentication
Un-auth VLAN 40 (Guest VLAN)
Auth VLAN 11 (Workstation VLAN)

I'm using Microsoft NAP, and i am having some trouble finding out how i should handle all my IP phones. - They are in a separate port, so they cant be authenticated by my radius server, and by default, they will move to VLAN 40 (guest network). I can live with the ip phones getting on VLAN 11, because i have a untagged 11, tagged 10 setup, and it is working fine.

VLAN 10 is VOIP vlan.

Can i some some, mac address match / check from a list of mac, or maybe a mac-addresses pattern?

Thank you!

/Mick
3 REPLIES
cenk sasmaztin
Honored Contributor

Re: 802.1x authentication with IP phones?

cenk sasmaztin
Honored Contributor

Re: 802.1x authentication with IP phones?

or 802.1x supplicant configuration on ip phone same pc


for example ip phone configuration
http://wiki.siemens-enterprise.com/images/archive/c/cb/20080612100423!Layer_2_authentication_on_VoIP_phones_(802.1x).pdf

cenk

Jeff Carrell
Honored Contributor

Re: 802.1x authentication with IP phones?

Altho you can do mac addr authentication for 802.1X, it is less secure compared to a device that has a supplicant.

The issues for mac addr auth:
1) the uid/pw in AD must be the same, unless you can do #2. The issue with uid/pw being the same is it violates the default password complexity rules in AD, but you can configure a specific group pw complex policy to get around that (W2K3/AD did not have this feature!)

2) depending on which HPN switch you have, it may be possible to set a different pw for a mac addr in the switch config, but it requires the phones to stay there, and as you add phones you have to add more entries...it does not scale well. -and you may hit the pw complex rule again, but it can be changed.

3) NAP does not have a way to look at prefix only for basic pattern match, at least not that I have found.

Now, there are some benefits with NAP that can ease some of the less-secureness of mac auth, you can set in the connection profile (I think conn profile, it's been 1+yrs since I've done NAP/NPS this way) that the device must match a manufacturer type and/or device type. So as a device comes in, even if someone trys to spoof the mac addr, other components must match. You can also lock it down to the device must be wired and not wireless.

The other downside to 802.1X auth, it did not (originally) have support to pass back info to a switch to put a port "tagged" into a vlan. RFC-4675 added that functionality, but Microsoft doesn't support it at all, I have been asking then for 2 yrs for it. ProVision ASIC switches from HP-ProCurve have had this for 2yrs: 3500/5400/6200/6600/8200. (FreeRADIUS 2.0+ has it too).

So you could auth a VoIP phone, but you are still required to have the port tagged in the voip-vlan. I would do that and have the port untagged in a "dead" or unused vlan -or- not even untagged in any vlan if it was a VoIP phone only on that port, and the phone was configured to speak 802.1Q upon power-up.

A device without a 802.1X supplicant just doesn't have the same benefits.

hth...Jeff