Hi Yaron, The original version of the draft did not require that the new TCP connection begin with an IKE message, but it was added in response to feedback we received at our meeting in Yokohama.
The concern was that the new TCP connection would almost certainly have different ports from the old connection. In order for the server to send packets back to the client, it needs to know the correct mapping for both the IKE SAs and the Child SAs. If we allow an ESP packet to be the first packet of a new connection, it may be hard to implement a correct server that reacts to that and adjusts all associated IKE and Child SA values to use the new port. However, it the first packet is an IKE packet, the server can essentially treat it as if it were MOBIKE and reset the ports. In the case of multiple IKE SAs over a TCP connection (which is a new edge case that has been brought up), perhaps it would make sense to say that for all IKE SAs using the connection, at least one IKE message must precede any ESP messages for a Child SA of the IKE SA. Does this make sense? Thanks, Tommy > On Dec 8, 2015, at 2:12 AM, Yaron Sheffer <[email protected]> wrote: > > Hi Samy, > > Thanks for the new draft. It addresses most of my comments, but one question > remains. > > I still don't understand why we require that each connection should start > with an IKE message. The explanation given is "to allow the peer to know with > which IKE session the traffic is associated." But of course the ESP SPI > identifies the Child SA, and implicitly, the IKE SA. > > Moreover, later in the same section you allow multiple IKE SAs over the same > connection, which again doesn't work well with the reasoning above. > > Best, > Yaron > > On 12/08/2015 08:40 AM, Samy Touati wrote: >> Hi Yaron and Yoav, >> >> An updated draft addressing your comments has been posted. >> >> https://www.ietf.org/internet-drafts/draft-pauly-ipsecme-tcp-encaps-02.txt >> <https://www.ietf.org/internet-drafts/draft-pauly-ipsecme-tcp-encaps-02.txt> >> >> Please check it out, and provide feedback. >> >> >> Thanks. >> Samy. >> >> >> From: Yaron Sheffer < <mailto:[email protected]>[email protected] >> <mailto:[email protected]>> >> Sent: Nov 20, 2015 3:11 PM >> To: Tommy Pauly; IPsecME WG >> Subject: Re: [IPsec] New revision of TCP Encapsulation draft >> >> Hi Tommy, >> >> I also think this is very relevant work. Here are some comments to -01: >> >> I think that Yoav's draft, draft-nir-ipsecme-ike-tcp-01, should be cited >> under "prior work", both because it is documented and also because I >> believe it is implemented by a vendor. >> >> In Sec. 1, under the UDP encapsulation, I suggest to add "Often peers >> will use UDP encapsulation even when there is no NAT on the path, for >> example because networks or middleboxes do not support IP protocols >> other than TCP and UDP." >> >> "Although a stream" - this paragraph is not worded very well (streams >> don't send anything) and is hard to understand. There are lots of >> networks that use jumbo frames and so hardcoding the value 1500 into the >> spec may not be a good idea. >> >> I can think of HA cases where several gateways are handling ESP SAs that >> are all associated with the same IKE SA. So I'm wondering why we are >> insisting on all Child SAs being in the same connection, and as a result >> requiring that an IKE message be the preamble to any new connection. >> >> Although it might seem obvious, I think Sec. 3 should say explicitly >> that if the connection is closed midway through a message, the recipient >> must silently drop the partial message. >> >> You may want to add to the last paragraph of the Security >> Considerations: This document explicitly does not define a profile for >> TLS when used in this manner, or any relation between identities at the >> IPsec level and those at the TLS level ("channel binding"). >> >> Thanks, >> Yaron >> >> On 11/20/2015 11:49 PM, Tommy Pauly wrote: >> > Hello, >> > >> > Based on the feedback received at our informal meeting in Yokohama, I’ve >> > updated the draft for TCP Encapsulation of IKEv2 and ESP: >> > >> > https://tools.ietf.org/html/draft-pauly-ipsecme-tcp-encaps-01 >> > <https://tools.ietf.org/html/draft-pauly-ipsecme-tcp-encaps-01> >> > >> > The revisions include: >> > - More explanation in the introduction about the motivation, and other >> > work that this draft is trying to standardize (3GPP recommendations, >> > proprietary IKEv1 IPSec over TCP versions, and SSL VPNs). >> > - Comments about maximum IKE and ESP message size within the TCP stream, >> > which is effective the MTU of the tunnel. >> > - Specify that if the TCP connection is brought down and re-established, >> > the first message on the stream must be an IKE message. >> > - Detailed considerations about interactions with middleboxes (thanks >> > Graham Bartlett for input on this). >> > >> > In the meeting in Yokohama, there was general agreement that this was >> > relevant work that we’d like to keep looking into. Please read the >> > document, and provide any feedback you have! >> > >> > Thanks, >> > Tommy >> > _______________________________________________ >> > IPsec mailing list >> > [email protected] <mailto:[email protected]> >> > https://www.ietf.org/mailman/listinfo/ipsec >> > <https://www.ietf.org/mailman/listinfo/ipsec> >> > >> >> _______________________________________________ >> IPsec mailing list >> [email protected] <mailto:[email protected]> >> https://www.ietf.org/mailman/listinfo/ipsec >> <https://www.ietf.org/mailman/listinfo/ipsec> >> >> >> >> _______________________________________________ >> IPsec mailing list >> [email protected] <mailto:[email protected]> >> https://www.ietf.org/mailman/listinfo/ipsec >> <https://www.ietf.org/mailman/listinfo/ipsec> > > _______________________________________________ > IPsec mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/ipsec
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