Re: [TLS] Questions about TLS Server Name Indication extension
Michael D'Errico <mike-list@pobox.com> Sat, 31 October 2009 02:11 UTC
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Date: Fri, 30 Oct 2009 19:12:55 -0700
From: Michael D'Errico <mike-list@pobox.com>
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Subject: Re: [TLS] Questions about TLS Server Name Indication extension
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> Btw. RFC-4366 doesn't say what to do about IP-Addresses. Since > rfc-2818.txt indicates that Server certificates may contain > SANs of the type iPAddress, sending IP-Addresses also via SNI > sounds like the way to go when e.g. the Browser tries to open > a URL with only an IPaddress instead of a hostname.. RFC 4366 says on page 10: Literal IPv4 and IPv6 addresses are not permitted in "HostName". A new name type would need to be created for IP addresses. > There are much more interesting questions: when a TLS session in the > cache was originally established with protocol version 0x03,0x01 > what about a client resume proposal with a protocol version 0x03.0x00 > or 0x03,0x02 in the client_version of the ClientHello? I looked at my code and found that when a cached session is retrieved, the ClientHello.version of the new handshake is compared to the negotiated version of the original session. If they are not equal, then a full handshake is performed. But that brings up a subtle point. What if the client originally connected offering a higher version than I support? When it tries to resume a session, should it use the version it originally sent in the ClientHello, or the lower version that was negotiated? I would think that the client should be allowed to specify the same version number it originally connected with. I searched through RFC 5246 but could not find a discussion of this. Did I miss it? What do others think should happen? > A TLS client should *NEVER* make assumptions about independent > servers (i.e. independent ServerNames) sharing a TLS session cache. > Sensible TLS clients should NOT assume that TLS servers on different > ports of the same host share the TLS session cache (or credentials > or any other TLS characteristics, for that matter). A somewhat related problem I encountered is that Google's search engine assumes that the content at http port 80 is the same as the content at https port 443. I was having trouble getting my site indexed because the text/plain page from my TLS test server was being treated as my home page by Google's bot, i.e. with no links. I don't know if other search engines exhibit this behavior. Mike
- [TLS] Questions about TLS Server Name Indication … Nelson B Bolyard
- Re: [TLS] Questions about TLS Server Name Indicat… Nelson B Bolyard
- Re: [TLS] Questions about TLS Server Name Indicat… Wan-Teh Chang
- Re: [TLS] Questions about TLS Server Name Indicat… Michael D'Errico
- Re: [TLS] Questions about TLS Server Name Indicat… Nelson B Bolyard
- Re: [TLS] Questions about TLS Server Name Indicat… Michael Gray
- Re: [TLS] Questions about TLS Server Name Indicat… Wan-Teh Chang
- Re: [TLS] Questions about TLS Server Name Indicat… Peter Gutmann
- Re: [TLS] Questions about TLS Server Name Indicat… Martin Rex
- Re: [TLS] Questions about TLS Server Name Indicat… Martin Rex
- Re: [TLS] Questions about TLS Server Name Indicat… Nelson B Bolyard
- Re: [TLS] Questions about TLS Server Name Indicat… Nelson B Bolyard
- Re: [TLS] Questions about TLS Server Name Indicat… Martin Rex
- Re: [TLS] Multiple domain names in SNI (was Quest… Michael D'Errico
- Re: [TLS] Multiple Session Caches and SNI (was Qu… Michael D'Errico
- Re: [TLS] Multiple domain names in SNI (was Quest… Martin Rex
- Re: [TLS] Renegotiation with SNI after initial co… Michael D'Errico
- Re: [TLS] Multiple domain names in SNI (was Quest… Michael D'Errico
- Re: [TLS] Multiple Session Caches and SNI (was Qu… Martin Rex
- Re: [TLS] Multiple domain names in SNI (was Quest… Martin Rex
- Re: [TLS] Questions about TLS Server Name Indicat… Nelson B Bolyard
- Re: [TLS] Multiple Session Caches and SNI Michael D'Errico
- Re: [TLS] Multiple domain names in SNI (was Quest… Michael Gray
- Re: [TLS] Multiple domain names in SNI (was Quest… Michael D'Errico
- Re: [TLS] Requiring SNI for resumption (was Quest… Michael D'Errico
- Re: [TLS] Multiple Session Caches and SNI Martin Rex
- Re: [TLS] Multiple Session Caches and SNI Michael D'Errico
- Re: [TLS] Questions about TLS Server Name Indicat… Michael D'Errico
- Re: [TLS] Questions about TLS Server Name Indicat… Pasi.Eronen