Hi Erik, As far as it goes, this might work. However, I'm not sure about the effect of this on compatibility. I'm concerned that maybe this would end up causing some servers to choke. Servers that receive SNI can sometimes use that SNI value to lookup the correct certificate. Your design could have those servers searching for a certificate that doesn't exist.
Anything along these lines would need to be tested for compatibility - extensively - before it could even be trialed. (I never saw the DDR as having deployment problems along these lines. It isn't THAT hard to know your own IP address for that purpose.) On Wed, Jul 27, 2022, at 14:38, Erik Nygren wrote: > Following discussions in ADD around the DDR draft (as well as in UTA > around Martin Thomson's PR to add IP address SANs to 6125-bis), > I wrote up a draft on how IP addresses might be represented in SNI: > > https://datatracker.ietf.org/doc/draft-nygren-tls-ip-in-sni/ > > There are at least three different ways we could do it, but this draft > proposes what seems to be the least bad while also talking about the > other alternatives. (I suspect we'd want to move the alternatives > to an appendix or remove entirely from a final version.) > > Is this interesting to the working group? > While IP address SANs have a bunch of corner cases and gaps, > they do seem to be picking up new uses. > > What motivated me to realize we need to solve this is that > draft-ietf-add-ddr uses IP SANs in a new way. Rather than the > client connecting to an IP address and expecting to see a SAN > (where returning a cert associated with the IP address containing > a SAN that the client connected to is straight-forward), > DDR has clients connecting to a different IP and then > expects to find an original IP also in the SAN list. > This means that for an ISP with a large number of IPs > (or using a services who operates DoH service on-behalf > of many entities), you'd need to quickly/wastefully burn through IPv4 > addresses to enable a unique cert per original IP. > > Erik > > > ---------- Forwarded message --------- > From: <internet-dra...@ietf.org> > Date: Wed, Jul 27, 2022 at 2:20 PM > Subject: New Version Notification for draft-nygren-tls-ip-in-sni-00.txt > To: Erik Nygren <erik+i...@nygren.org <mailto:erik%2bi...@nygren.org>>, > Rich Salz <rs...@akamai.com> > > > > A new version of I-D, draft-nygren-tls-ip-in-sni-00.txt > has been successfully submitted by Erik Nygren and posted to the > IETF repository. > > Name: draft-nygren-tls-ip-in-sni > Revision: 00 > Title: Representing IP addresses in TLS Server Name Indication > (SNI) > Document date: 2022-07-27 > Group: Individual Submission > Pages: 7 > URL: > https://www.ietf.org/archive/id/draft-nygren-tls-ip-in-sni-00.txt > Status: > https://datatracker.ietf.org/doc/draft-nygren-tls-ip-in-sni/ > Htmlized: > https://datatracker.ietf.org/doc/html/draft-nygren-tls-ip-in-sni > > > Abstract: > This specification provides a mechanism for clients to send IP > addresses in a TLS Server Name Indication (SNI) extension as part of > TLS handshakes, allowing servers to return a certificate containing > that subjectAltName. This is done by converting the IP address to a > special-use domain name. > > > > > The IETF Secretariat > > > _______________________________________________ > TLS mailing list > TLS@ietf.org > https://www.ietf.org/mailman/listinfo/tls _______________________________________________ TLS mailing list TLS@ietf.org https://www.ietf.org/mailman/listinfo/tls
