RE: iSCSI: IPsec tunnel / transport mode decision

["Bill Strahm" <bill@sanera.net>]

Funny because RFC 2401 says (Section 4.1)
"
In summary,
           a) A host MUST support both transport and tunnel mode.
           b) A security gateway is required to support only tunnel
              mode.  If it supports transport mode, that should be used
              only when the security gateway is acting as a host, e.g.,
              for network management.
"

I am assuming that at least one end of the iSCSI implementation is a Host
(if not both ends) and therefore will have a conformant IPsec
implementation...

Now the question is where do we want to allow security endpoints to be.  If
we want to allow only host-host security (and the requisite policy
nightmares) then Transport Mode will work.  However if we want to allow
Tunneling between hosts and security gateways, then Tunnel mode will need to
be used.  In reality I think we should stick with the 2401 requirements,
that way I don't have to write my own implementation...

I have not seen a call of consensus on this issue, have you issued it David
?

Bill
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-----Original Message-----
From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu]On Behalf Of
Saqib Jang
Sent: Thursday, November 01, 2001 10:03 AM
To: Ofer Biran; ips@ece.cmu.edu
Subject: RE: iSCSI: IPsec tunnel / transport mode decision


I thought the latest security draft already closed
on this issue.

>From Section 2.3 of -04 draft.
iSCSI security implementations MUST support ESP in transport mode.

Saqib

-----Original Message-----
From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu]On Behalf Of
Ofer Biran
Sent: Thursday, November 01, 2001 4:31 AM
To: ips@ece.cmu.edu
Subject: iSCSI: IPsec tunnel / transport mode decision


I'd like to drive this open issue into group consensus. It seems to
me that the tendency was more toward making tunnel mode a MUST as iFCP
and FCIP did, mainly due the option of integrating an existing IPsec
chip/box with the iSCSI implementation offering. If we reach this decision,
we may choose even not to mention transport mode (as MAY or some other
recommending text).

There is an excellent analysis made by Bernard Aboba in Section
"5.1. Transport mode versus tunnel mode" of draft-ietf-ips-security-04
( http://www.ietf.org/internet-drafts/draft-ietf-ips-security-04.txt )
that can help us with this decision (also Section "5.2. NAT traversal" is
relevant).

   Regards,
     Ofer

Ofer Biran
Storage and Systems Technology
IBM Research Lab in Haifa
biran@il.ibm.com  972-4-8296253