Re: [TLS] Session Lifetime

Eric Rescorla <ekr@rtfm.com> Mon, 29 November 2010 16:57 UTC

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Date: Mon, 29 Nov 2010 08:58:38 -0800
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From: Eric Rescorla <ekr@rtfm.com>
To: mrex@sap.com
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Subject: Re: [TLS] Session Lifetime
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The upper limit is just a suggestion anyway.

I'm unaware of any reason why weeks to months isn't acceptab;e.

-Ekr


On Wed, Nov 17, 2010 at 6:51 PM, Martin Rex <mrex@sap.com> wrote:

> Michael D'Errico wrote:
> >
> > Can someone point me to a document that explains why TLS
> > sessions should expire within minutes of creation, as is
> > the current practice (that I'm aware of)?
>
> I am only aware of an upper lifetime limit of 24h for cached TLS session
> in the SSLv3 and TLS specs, e.g. here:
>
> http://tools.ietf.org/html/rfc5246.txt#appendix-F.1.4
>
> For our apps I'm currently shipping a default session cache lifetime
> of 15 minutes for the server and 30 minutes for the client.
> Although this is a fairly short lifetime, it is perfectly sufficient
> to achieve an acceptable ratio of full-HS/resume-HS.
> Customers can finetune session cache size and cache lifetime.
>
> I don't know what other implementations and apps are using.
>
> -Martin
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