Re: [IPsec] Clarification on identities involved in IKEv2 EAPauthentication

["Amjad Inamdar (amjads)" <[e-mail]>]

Hi Yaov,

Thanks for your reply. Please see my comments inline. 

-----Original Message-----
From: Yoav Nir [mailto:[e-mail]] 
Sent: Tuesday, November 10, 2009 5:29 PM
To: Amjad Inamdar (amjads)
Cc: [e-mail]
Subject: Re: [IPsec] Clarification on identities involved in IKEv2
EAPauthentication


On Nov 10, 2009, at 1:40 PM, Amjad Inamdar (amjads) wrote:

> Hi,
>
> With IKEv2 EAP authentication, there are 3 identities involved
>
> 1) IDi - IKEv2 initiator identity sent in msg-3
> 2) EAP identity that gateway (IKE2 responder) can request from the 
> client (IKEv2 initiator)
> 3) Authenticated EAP identity that third party EAP server provides to 
> the gateway (IKEv2 responder).
>
>
> Could someone please clarify from RFC standpoint if
>
> 1) The 3 identities mentioned above MUST/SHOULD be same

No, although they typically are.

[Amjad]
Is there a use case for not having IDi same as EAP identity? Having them
same would simplify policy decisions.

> 2) If not same, what purpose should each of the above identities serve

   1) mainly used as a hint for the gateway as to which AAA server to
choose

[Amjad]
EAP authentication is typically used with remote access and IDi of type
IP_ADDR may not be very useful here as a hint for AAA server. So it will
help to have recommened ID types for such cases.

   2) It's the AAA server that may request the identity, and it's
internal to AAA. It doesn't play in IKE

[Amjad]
Does it mean that if gateway is just acting as a pass-through, gateway
MUST-NOT request EAP identity from the client as per RFC? If AAA server
does not provide authenticated identity to the gateway (RFC does not
seem to mandate that), the only way for gateway is to request EAP
identity from the client, for policy decisions, unless IDi carries EAP
identity which again is not mandated by RFC.

   3) That's the authenticated identity of the user. That is what the
responder uses for policy decisions.

> 3) The mandatory/recommended format for each of the above identites

All the types in section 3.5 are acceptable, but the most used ones are
ID_RFC822_ADDR and ID_DER_ASN1_DN
[Amjad]
Are IKEv2 identity types acceptable as EAP identity as well?

Thanks,
-Amjad