Re: [TLS] RFC-4366-bis and the unrecognized_name(112) alert

Michael D'Errico <mike-list@pobox.com> Wed, 09 June 2010 17:16 UTC

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Date: Wed, 09 Jun 2010 10:16:41 -0700
From: Michael D'Errico <mike-list@pobox.com>
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To: Paul Hoffman <paul.hoffman@vpnc.org>
References: <4C0FA538.7050309@pobox.com> from "Michael D'Errico" at Jun 9, 10 07:29:12 am <201006091456.o59EukJ3015376@fs4113.wdf.sap.corp> <AC1CFD94F59A264488DC2BEC3E890DE50AA7E552@xmb-sjc-225.amer.cisco.com> <p0624083bc83572582a36@[10.20.30.158]>
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Cc: tls@ietf.org
Subject: Re: [TLS] RFC-4366-bis and the unrecognized_name(112) alert
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Paul Hoffman wrote:
> 
> ... there is still not enough definitive wording. I propose:
> 
> The ServerNameList MUST NOT contain more than one name of the same
> name_type.  If the server understood the ClientHello extension but
> does not recognize the server name, the server SHOULD take one of two
> actions: abort the handshake by sending a fatal
> unrecognized_name(112) alert, or continue the handshake using a
> default credential. Sending a warning-level alert such as
> unrecognized_name(112), but continuing the handshake, is NOT
> RECOMMENDED because the client's expected behavior in response to
> this is unpredictable.

The last sentence makes it unclear whether sending the alert is not
recommended or if continuing the handshake is not recommended.

Mike