Hi Vijay, Sending "REDIRECT" notification upon receiving IKE_SA_INIT request solves the load issue.
Sending "REDIRECT" notification as part of first IKE_AUTH response satisfies selection of VPN responder based on IDi. Based on my understanding, even 3GPP IMSI is sent along with IDi. This information (typically some portion of it) can be used to figure out the right VPN Server to redirect. Yet times, based on the type of internal network the user is accessing, VPN server might decide to redirect the user to some other VPN Server to improve user experience. I guess this case is handled in the draft under section 'Gateway Initiated Redirect". Though it seems fine sending "Redirect" notification along with "EAP SUCCESS" as part of AUTH response, I am wondering the deployment use cases for this. If Authentication is successful, then I guess majority of heavy work is already done by VPN gateway and it is better if it continues to serve the user. Regards Srini -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Vijay Devarapalli Sent: Monday, March 16, 2009 3:56 PM To: Yaron Sheffer Cc: IPsecme WG; Tero Kivinen Subject: Re: [IPsec] Redirect during IKE_AUTH (was Re: WG LastCall:draft-ietf-ipsecme-ikev2-redirect-04) Yaron Sheffer wrote: > Hi Vijay, > > I don't have the details at hand, but in 3GPP land it is common for the > client to send all sorts of temporary identities, and for the AAA server to > respond to the Packet Data Gateway (that's our gateway) with the client's > "true" identity (IMSI, MSISDN, whatever). Such permanent identity could > serve as the basis for a redirect decision. Do we have people on the list > familiar with these specs? I am aware of these specs. The last EAP message with "Success" from the AAA server to the gateway, has the real identity of the client as a RADIUS attribute (for example). But we don't have a reference for this in the IETF, since RFC 4306 says that there shouldn't be an EAP Identity Request/Response exchange. In RFC 4877, we did mention that the Mobile IPv6 home agent MUST acquire the true identity of the mobile node when EAP is used, but left the actual mechanism out of scope. Section 8 of RFC 4877 says When EAP is used, the identity presented by the mobile node in the IDi field may not be the actual identity of the mobile node. It could be set to an identity that is used only for Authentication, Authorization, and Accounting (AAA) routing purposes and selecting the right EAP method. It is possible that the actual identity is carried inside EAP, invisible to the home agent. While IKEv2 does not allow an EAP Identity Request/Response message exchange, EAP methods may exchange identities within themselves. In this case, the home agent MUST acquire the mobile node's identity from the corresponding AAA server. How the home agent acquires the mobile node's identity is out of scope for this document. One option would to be adapt the above text to say that if the client had presented a temporary identity to the gateway in the IKE_AUTH request message and the gateway does acquire the real identity of the client after the EAP exchange, then the gateway can decide to redirect based on the true identity. The REDIRECT payload would then be sent in the IKE_AUTH response that carries the EAP success message. Vijay > > Thanks, > Yaron > >> -----Original Message----- >> From: Vijay Devarapalli [mailto:[email protected]] >> Sent: Tuesday, March 17, 2009 0:12 >> To: Yaron Sheffer; Tero Kivinen >> Cc: IPsecme WG >> Subject: RE: [IPsec] Redirect during IKE_AUTH (was Re: WG Last Call:draft- >> ietf-ipsecme-ikev2-redirect-04) >> >> Hi Yaron, Tero, >> >> We don't really have a protocol extension (EAP, RADIUS or Diameter) for >> the AAA server to tell the IKEv2 gateway to redirect the client to >> another gateway. >> >> In addition, if there is an EAP exchange, the true identity of the >> client is not revealed to the gateway. >> >> So I am not sure on what basis the gateway would redirect the client in >> message #10 and #18 in Tero's email. >> http://www.ietf.org/mail-archive/web/ipsec/current/msg04025.html >> >> My proposal is to limit the REDIRECT payload to appear in message #4 (in >> the first IKE_AUTH response), based on the identity presented by the >> client. And leave EAP scenarios out of scope for this document. If >> someone wants the AAA server to redirect the client based on the EAP >> exchange, a separate document could be written. And this document can >> specify that the REDIRECT message can be sent in message 10. >> >> Does this sound good? >> >> Vijay >> >> On Thu, 2009-03-12 at 16:07 -0400, Yaron Sheffer wrote: >>> We should not do the redirect based on an asserted, unautheticated >> identity. >>> Going back to Tero's previous message on this thread, I think we should >>> allow redirect both in message 10 and 18 (i.e. following both EAP >> rounds, >>> and where the EAP state machine is "idle"). The gateway probably needs >> the >>> AAA server to tell it where to redirect to, anyway. >>> >>> In message 10 the gateway still doesn't know that the client wants to >>> perform secondary authentication, but I propose to ignore this issue for >>> simplicity. >>> >>> Thanks, >>> Yaron >>> >>>> -----Original Message----- >>>> From: [email protected] [mailto:[email protected]] On Behalf >> Of >>>> Tero Kivinen >>>> Sent: Thursday, March 12, 2009 14:15 >>>> To: Vijay Devarapalli >>>> Cc: IPsecme WG; Yoav Nir; [email protected] >>>> Subject: Re: [IPsec] Redirect during IKE_AUTH (was Re: WG Last Call: >>>> draft-ietf-ipsecme-ikev2-redirect-04) >>>> >>>> Vijay Devarapalli writes: >>>>> The one significant piece of information that the gateway has during >> the >>>>> IKE_AUTH exchange, that it didn't have during the IKE_SA_INIT >> exchange, >>>>> is the identity of the client. Some folks want to redirect the >> client >>>>> based on whatever identity it presents. So if thats they case, the >> first >>>>> IKE_AUTH response would be used for sending the REDIRECT payload. If >> the >>>>> gateway wanted to redirect the client because of load conditions, it >>>>> would have done it during the IKE_SA_INIT exchange itself. I don't >>>>> expect the EAP exchange or the multiple auth exchange to trigger a >>>>> redirect. We can make this explicit if needed. >>>> I tought someone wanted to do some kind of radius lookup to select >>>> where client is redirected to and in some cases client might not be >>>> sending the ID used for that in the ID payload but might use the EAP >>>> identity request/reply (even though RFC4306 3.16 says SHOULD NOT). >>>> >>>> If it will be enough to only see IDi to do redirect, meaning we can >>>> always restrict the REDIRECT to message 4, then it might be even >>>> acceptable to make that change. The main reason I was against having >>>> REDIRECTS in IKE_AUTHs is that there is so many locations where it can >>>> be and testing all possible combinations with all possible >>>> authentication methods and other extensions gets very complicated. >>>> -- >>>> [email protected] >>>> _______________________________________________ >>>> IPsec mailing list >>>> [email protected] >>>> https://www.ietf.org/mailman/listinfo/ipsec >>>> >>>> Scanned by Check Point Total Security Gateway. >>>> >>>> Scanned by Check Point Total Security Gateway. >> Scanned by Check Point Total Security Gateway. _______________________________________________ IPsec mailing list [email protected] https://www.ietf.org/mailman/listinfo/ipsec _______________________________________________ IPsec mailing list [email protected] https://www.ietf.org/mailman/listinfo/ipsec
