Re: [pcp] Comparison of PCP authentication
"Dan Wing" <dwing@cisco.com> Thu, 09 August 2012 17:07 UTC
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From: Dan Wing <dwing@cisco.com>
To: "'Zhangdacheng (Dacheng)'" <zhangdacheng@huawei.com>, 'Margaret Wasserman' <mrw@lilacglade.org>, hartmans@painless-security.com
References: <9B57C850BB53634CACEC56EF4853FF653B6EC381@TK5EX14MBXW604.wingroup.windeploy.ntdev.microsoft.com> <7FE144CF-00E3-4451-8CBE-A6A684DB7CC4@yegin.org> <067d01cd73fd$765a6c50$630f44f0$@com> <D6D2DEED-C35A-45AB-8B72-96195C308DB9@yegin.org> <57FF0F8E-1B86-410F-8B6B-C4893A28222F@lilacglade.org> <BB72B80F-0622-4A5B-A985-79D8AED13E0B@apple.com> <003b01cd7587$a111b760$e3352620$@com> <15990E87-2D59-49B1-845C-2A4CB5A1FBD6@lilacglade.org> <008801cd758f$3fd306e0$bf7914a0$@com> <C72CBD9FE3CA604887B1B3F1D145D05E2CE65225@szxeml528-mbx.china.huawei.com> <028801cd75d6$c5765490$5062fdb0$@com> <C72CBD9FE3CA604887B1B3F1D145D05E2CE6527F@szxeml528-mbx.china.huawei.com>
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Date: Thu, 09 Aug 2012 10:07:08 -0700
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Cc: pcp@ietf.org
Subject: Re: [pcp] Comparison of PCP authentication
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> -----Original Message----- > From: Zhangdacheng (Dacheng) [mailto:zhangdacheng@huawei.com] > Sent: Wednesday, August 08, 2012 11:07 PM > To: Dan Wing; 'Margaret Wasserman'; hartmans@painless-security.com > Cc: pcp@ietf.org > Subject: RE: [pcp] Comparison of PCP authentication > > If a client has been configured to support PANA, then it is more likely > to stay in an environment where authentication is required, is it? ^_^ On the other hand, it would be annoying if configuring PCP authentication for one network (e.g., office network) added a round trip when on networks that don't need PCP authentication (e.g., home network, airport, hotel, 3G/LTE network). Heuristics to decide "same network" or "different network" are probably helpful for PCP to distinguish those networks (e.g., DNAv4 [RFC4436]). > However, if this assumption is broken, then two approaches do not make > big differences. Two approaches force additional code and test cases. -d > > > > From: Dan Wing [mailto:dwing@cisco.com] > > Sent: Thursday, August 09, 2012 10:29 AM > > To: Zhangdacheng (Dacheng); 'Margaret Wasserman'; > > hartmans@painless-security.com > > Cc: pcp@ietf.org > > Subject: RE: [pcp] Comparison of PCP authentication > > > > > -----Original Message----- > > > From: Zhangdacheng (Dacheng) [mailto:zhangdacheng@huawei.com] > > > Sent: Wednesday, August 08, 2012 6:57 PM > > > To: Dan Wing; 'Margaret Wasserman'; hartmans@painless-security.com > > > Cc: pcp@ietf.org > > > Subject: RE: [pcp] Comparison of PCP authentication > > > > > > Slide 5 only illustrates a scenario where the pcp server initiates > the > > > authentication procedure. But in our draft, it is also described > that > > > the client can initiate authentication proactively. In my opinion, > this > > > approach seems even more preferable. ^_^ > > > > Depends on if we want to optimize for the case where PCP > authentication > > is necessary or is unnecessary. > > > > Doing PANA first is a good optimization only if the PCP client knows > > that PCP authentication will be required by the PCP server on that > > particular network. If PCP authentication is not needed on a > particular > > network, requesting PCP authentication incurs an extra round trip. > > > > If the PCP server doesn't want authentication, I believe we can > always > > rely on a PCP error response if for PANA messages and for > > PCP-encapsulated (tunneled) PANA messages (which I believe are the > two > > proposals being considered) -- thus, we won't have timeouts due to > > requesting authentication, which is good. > > > > -d > > > > > > > > > > -----Original Message----- > > > > From: pcp-bounces@ietf.org [mailto:pcp-bounces@ietf.org] On > Behalf Of > > > Dan > > > > Wing > > > > Sent: Thursday, August 09, 2012 1:57 AM > > > > To: 'Margaret Wasserman'; hartmans@painless-security.com > > > > Cc: pcp@ietf.org > > > > Subject: Re: [pcp] Comparison of PCP authentication > > > > > > > > > -----Original Message----- > > > > > From: Margaret Wasserman [mailto:mrw@lilacglade.org] > > > > > Sent: Wednesday, August 08, 2012 10:07 AM > > > > > To: Dan Wing > > > > > Cc: 'james woodyatt'; pcp@ietf.org > > > > > Subject: Re: [pcp] Comparison of PCP authentication > > > > > > > > > > > > > > > On Aug 8, 2012, at 1:02 PM, Dan Wing wrote: > > > > > > So, I think we are okay -- assuming we keep the idea that the > PCP > > > > > > client tries to first send a PCP request (and not to first > send > > > > > > a PANA request). > > > > > > > > > > Actually, we don't keep this, even now. There is certainly a > > > notion > > > > > that a client could be configured to use authentication for all > (or > > > > > some) PCP exchanges, and that the authentication would come > first. > > > > > > > > But slide 5 of your deck, > > > > http://tools.ietf.org/agenda/84/slides/slides-84-pcp-10.pdf, > > > > shows the PCP client doing an initial PCP request and getting an > > > > AUTH_REQUIRED > > > > error. That is the basis of my (lovely) ASCII artistry. > > > > > > > > > > However, I do worry that implementations may optimize > themselves > > > > > > to send a PANA request first, which would cause the problem > you > > > > > > describe if they send the PANA request to a NAT-PMP server. > That > > > > > > is, this would be a problem: > > > > > > > > > > > > PCP client NAT-PMP server > > > > > > | | > > > > > > 1. |-------(authentication message)---->| > > > > > > 2. |<--NAT-PMP error--------------------| > > > > > > | | > > > > > > > > > > > > But the PCP client doesn't speak NAT-PMP, so there isn't a > way > > > > > > for it to handle that case, anyway (no matter if we had PCP > > > > > > authentication or not). > > > > > > > > > > > > In summary, I think we can skate around problems with talking > > > > > > to a NAT-PMP server. > > > > > > > > > > Makes sense. > > > > > > > > > > > > Sam Hartman wrote: > > > > > > > > > It's not just that implementations may optimize sending an > > > > > authentication request. > > > > > > > > > > An implementation MAY require authentication. > > > > > I.E. it is unwilling to send the request unless it has an > > > authenticated > > > > > channel. > > > > > For firewall control this makes a lot of sense. > > > > > > > > I believe we are okay -- the PCP client trying to do > authentication > > > will > > > > have to expect it will occasionally see a NAT-PMP error message. > > > That > > > > will occur if it is communicating with a NAT-PMP server (which > shares > > > the > > > > same port as PCP). If the PCP client receives a NAT-PMP error, > it > > > needs > > > > to abort trying to do PCP and abort trying to do PANA (because > > > neither > > > > will work); in the (unlikely) event the PCP client also > implements > > > > NAT-PMP, it can then downgrade to using NAT-PMP. > > > > > > > > A sentence or three in draft-ietf-pcp-authentication will be > needed > > > > to explain that a NAT-PMP error might be received. > > > > > > > > -d > > > > > > > > > > > > _______________________________________________ > > > > pcp mailing list > > > > pcp@ietf.org > > > > https://www.ietf.org/mailman/listinfo/pcp
- [pcp] Reminder: submit IETF 84 PCP agenda requests Dave Thaler
- Re: [pcp] Reminder: submit IETF 84 PCP agenda req… Xiaohong Deng
- [pcp] Comparison of PCP authentication Alper Yegin
- Re: [pcp] Comparison of PCP authentication Margaret Wasserman
- Re: [pcp] Comparison of PCP authentication Dan Wing
- Re: [pcp] Comparison of PCP authentication Alper Yegin
- Re: [pcp] Comparison of PCP authentication Margaret Wasserman
- Re: [pcp] Comparison of PCP authentication Dan Wing
- Re: [pcp] Comparison of PCP authentication james woodyatt
- Re: [pcp] Comparison of PCP authentication Margaret Wasserman
- Re: [pcp] Comparison of PCP authentication Margaret Wasserman
- Re: [pcp] Comparison of PCP authentication Sam Hartman
- Re: [pcp] Comparison of PCP authentication Yoshihiro Ohba
- Re: [pcp] Comparison of PCP authentication Zhangdacheng (Dacheng)
- Re: [pcp] Comparison of PCP authentication Alper Yegin
- Re: [pcp] Comparison of PCP authentication Alper Yegin
- Re: [pcp] Comparison of PCP authentication Margaret Wasserman
- Re: [pcp] Comparison of PCP authentication Margaret Wasserman
- Re: [pcp] Comparison of PCP authentication Alper Yegin
- Re: [pcp] Comparison of PCP authentication Yoshihiro Ohba
- Re: [pcp] Comparison of PCP authentication Alper Yegin
- Re: [pcp] Comparison of PCP authentication Margaret Wasserman
- Re: [pcp] Comparison of PCP authentication Sam Hartman
- Re: [pcp] Comparison of PCP authentication Alper Yegin
- Re: [pcp] Comparison of PCP authentication Margaret Wasserman
- Re: [pcp] Comparison of PCP authentication Yoshihiro Ohba
- Re: [pcp] Comparison of PCP authentication Dan Wing
- Re: [pcp] Comparison of PCP authentication Margaret Wasserman
- Re: [pcp] Comparison of PCP authentication Sam Hartman
- Re: [pcp] Comparison of PCP authentication Dan Wing
- Re: [pcp] Comparison of PCP authentication Zhangdacheng (Dacheng)
- Re: [pcp] Comparison of PCP authentication Dan Wing
- Re: [pcp] Comparison of PCP authentication Zhangdacheng (Dacheng)
- [pcp] single port PANA+PCP Alper Yegin
- Re: [pcp] single port PANA+PCP Margaret Wasserman
- Re: [pcp] Comparison of PCP authentication Sam Hartman
- Re: [pcp] single port PANA+PCP Alper Yegin
- Re: [pcp] single port PANA+PCP Dan Wing
- Re: [pcp] Comparison of PCP authentication Dan Wing
- Re: [pcp] single port PANA+PCP Dan Wing
- Re: [pcp] Comparison of PCP authentication Dan Wing
- Re: [pcp] Comparison of PCP authentication Sam Hartman
- Re: [pcp] Comparison of PCP authentication Dan Wing
- Re: [pcp] single port PANA+PCP Margaret Wasserman
- Re: [pcp] Comparison of PCP authentication Margaret Wasserman
- Re: [pcp] Comparison of PCP authentication Sam Hartman
- Re: [pcp] Comparison of PCP authentication Zhangdacheng (Dacheng)
- Re: [pcp] Comparison of PCP authentication Yoshihiro Ohba
- Re: [pcp] Comparison of PCP authentication Zhangdacheng (Dacheng)
- Re: [pcp] Comparison of PCP authentication Yoshihiro Ohba
- Re: [pcp] Comparison of PCP authentication Margaret Wasserman
- Re: [pcp] Comparison of PCP authentication Margaret Wasserman
- Re: [pcp] Comparison of PCP authentication Yoshihiro Ohba
- Re: [pcp] Comparison of PCP authentication Sam Hartman
- Re: [pcp] Comparison of PCP authentication Margaret Wasserman
- Re: [pcp] Comparison of PCP authentication Yoshihiro Ohba
- Re: [pcp] Comparison of PCP authentication Alper Yegin
- Re: [pcp] Comparison of PCP authentication Alper Yegin
- [pcp] channel binding (was Re: Comparison of PCP … Alper Yegin
- [pcp] PANA and PCP port sharing (was Re: Comparis… Alper Yegin
- Re: [pcp] Comparison of PCP authentication Sam Hartman
- Re: [pcp] channel binding Sam Hartman
- Re: [pcp] Comparison of PCP authentication Yoshihiro Ohba
- Re: [pcp] channel binding Alper Yegin
- Re: [pcp] Comparison of PCP authentication Alper Yegin
- Re: [pcp] Comparison of PCP authentication Zhangdacheng (Dacheng)
- [pcp] Fwd: Comparison of PCP authentication Subir Das
- Re: [pcp] Fwd: Comparison of PCP authentication Dan Wing
- Re: [pcp] Fwd: Comparison of PCP authentication Subir Das
- Re: [pcp] Fwd: Comparison of PCP authentication Sam Hartman