Subject: [eap] RE: [Isms] RADIUS is not a trusted third party

From: "Glen Zorn (gwz)" <[email-masked]>
Date: Sun, 17 Apr 2005 11:09:54 -0700

Tschofenig Hannes <> supposedly scribbled:

> hi sam,
> 
> you have intentionally chosen a provocative title for your mail.
> 
> you write:
> 
> "
>> Remember that RADIUS is a callout service; it is not a trusted
third
>> party.  In other words, in a particular SNMP authentication, only
one
>> of the parties will know that RADIUS is being used. "
> 
> what is a "callout service"?
> what is radius for you? (you write that it is not a trusted third
> party.) 

It's not.  From the point of view of authentication protocols (PAP,
CHAP, EAP, etc.), both RADIUS and Diameter are just "wires": the
operation of the auth protocols should be exactly the same as if
they terminated in the AAA client, instead of elsewhere.  Basically,
the purpose of AAA (again, from the POV of an authentication
protocol) is simply scaling.  BTW, a lot of misery has been caused
by the erroneous belief that EAP is (or can be) a three-party
authentication protocol: it isn't, and can't be.  It could _carry_ a
three-party protocol (like Kerberos), but EAP in itself is a
two-party protocol.

> why do you care that only one party knows that radius is
> used? it could also be diameter.  
> 
> i would like to better understand why some people dislike the aaa
> architecture (radius, diameter). 

I think that the misunderstanding mentioned above might have
something to do with it...

> 
> ciao
> hannes
> 
> 
>> -----Ursprüngliche Nachricht-----
>> Von: [email-masked]
>> [mailto:[email-masked]] Im Auftrag von Sam Hartman
>> Gesendet: Freitag, 15. April 2005 19:34
>> An: Martin Soukup
>> Cc: [email-masked]
>> Betreff: [Isms] RADIUS is not a trusted third party
>> 
>> 
>>>>>>> "Martin" == Martin Soukup <[email-masked]> writes:
>> 
>>     Martin> RADIUS "Access-Accept" indicates a successful
>>     Martin> authenthentication response for a user.
>> 
>>     Martin> The Access-Accept already returns a
"Session-Timeout",
>>     Martin> defined as "Sets the maximum number of seconds of
service
>>     Martin> to be provided to the user before the session
>>     Martin> terminates. This attribute value becomes the per-user
>>     Martin> "absolute timeout."".
>> 
>> This only tells the SNMP engine talking to the RADIUS server the
>> timeout.  You need to tell the other side of the exchange the
>> timeout too. 
>> 
>> Remember that RADIUS is a callout service; it is not a trusted
third
>> party.  In other words, in a particular SNMP authentication, only
one
>> of the parties will know that RADIUS is being used.
>> 
>> 
>> _______________________________________________
>> Isms mailing list
>> [email-masked]
>> https://www1.ietf.org/mailman/listinfo/isms
>> 
> 
> _______________________________________________
> Isms mailing list
> [email-masked]
> https://www1.ietf.org/mailman/listinfo/isms

Hope this helps,

~gwz

Why is it that most of the world's problems can't be solved by
simply
  listening to John Coltrane? -- Henry Gabriel
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---

From: Alper Yegin <[email-masked]>
Date: Tue, 19 Apr 2005 17:28:52 -0700

Glen,

> CHAP, EAP, etc.), both RADIUS and Diameter are just "wires": 

What happens when we look at this picture from the "authorization"
perspective? "Host-to-NAS authorization for the network access service"
is dynamically generated from "host-to-AAA server" authorization and
"AAA server to client (NAS)" authorization. Wouldn't this constitute a
3-party model?

Alper

> the

---

From: "Glen Zorn (gwz)" <[email-masked]>
Date: Tue, 19 Apr 2005 17:57:42 -0700

Alper Yegin <> supposedly scribbled:

> "AAA server to client (NAS)" authorization. Wouldn't this
constitute
> a 3-party model? 

I'm pretty sure that both Sam & I were just talking about
authentication.  In any case, could you expound a bit?  I don't
actually know what you're talking about.  What do "Host-to-NAS
authorization for the network access service", "host-to-AAA server
authorization" and "AAA server to client (NAS) authorization" mean?
Are you saying that somehow the host authorizes the NAS to provide
it network access?

>> operation of the auth protocols should be exactly the same as if
they
>> terminated in the AAA client, instead of elsewhere.  Basically,
the
>> purpose of AAA (again, from the POV of an authentication
>> protocol) is simply scaling.  BTW, a lot of misery has been
caused by
>> the erroneous belief that EAP is (or can be) a three-party
>>> why do you care that only one party knows that radius is used?
it
>>> could also be diameter. 
"Session-Timeout",
>>>>     service Martin> to be provided to the user before the
session
>>>> third party.  In other words, in a particular SNMP
authentication,
>>>> only one of the parties will know that RADIUS is being used.
>>>> 
>>>> 
simply

Hope this helps,

~gwz

---

From: Alper Yegin <[email-masked]>
Date: Wed, 20 Apr 2005 11:20:21 -0700

> authentication.  

I understand that.

> In any case, could you expound a bit?  I don't

The host (or the user on the host) is authorized to access the Internet
by relying on its subscription with an operator that runs the AAA
server. SLAs, credentials are used to encode this relation. [1]

A bunch of NASes are also authorized by the same AAA server to provide
access service to subscribers of that operator. This comes in the form
of roaming agreements (list of NAS identifiers, credentials, etc.) [2]

Now, if host1 wants to access the Internet via NAS1, the required
dynamic authorization (that host1 is allowed to access the Internet, and
NAS1 is allowed to provide this service) can be generated by relying on
[1] and [2].

I guess the AAA protocol that runs between the NAS and AAA server is a
"wire" as you said, but the AAA server is the trusted third party. Does
this make sense?

Alper