Subject: Question on draft-ietf-l2tpext-security-02.txt

From: Jhilmil Kochar <[email-masked]>
Date: Wed, 23 May 2001 15:38:01 +0530

Hi,
    I had 2 questions on this draft.
1.section 7.1
"The L2TP security protocol MUST provide authentication, integrity and
replay protection for control packets. In addition, it SHOULD protect
confidentiality of control packets. It MUST provide integrity and replay
protection of data packets, and MAY protect confidentiality of data
packets. An L2TP security protocol MUST also provide a scalable approach
to key management."
The draft does not talk of requirement of authentication of data packets. Why?

2. what happens to control plane security as defined in L2TP draft using H
bit, Random vector and MD5 hashing in the presence of IPSEC security? The
draft does not talk of this. Taking care of  both would mean duplicating the
effort so that should mean that data hiding in control plane should be
disabled by default when IPSEC is enabled.

Thanks in advance
Jhilmil Kochar

--

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Jhilmil Kochar
Technical Manager
Globespan India
E-mail:mailto:[email-masked]
Web: http://www.globespan.net

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From: Skip Booth <[email-masked]>
Date: Thu, 24 May 2001 13:22:13 -0400

> The draft does not talk of requirement of authentication of data packets. Why?

"It MUST provide integrity and replay protection of data packets"

I believe integrity at least in the sense of IPsec implies authentication.
Would it make you happy if this sentence where worded:

"It MUST provide authentication, integrity and replay protection of data
packets"

> disabled by default when IPSEC is enabled.

I personally don't think this is an area that the draft needs to focus
on. Just because the L2TP packets are being protected by IPsec doesn't rule
out the need to do AVP hiding.  For instance, the IPsec SA may only be
providing authentication/integrity checking of the control packets and thus
it's still desirable to use AVP hiding for confidentiality of AVPs.

-Skip