[Standards-JIG] NEW: JEP-0170 (Recommended Order of Stream Feature Negotiation)

Jacek Konieczny jajcus at jajcus.net
Wed Jan 11 20:47:35 UTC 2006

On Wed, Jan 11, 2006 at 12:55:06PM -0700, Peter Saint-Andre wrote:
> Jesus Cea wrote:
> >Since compression can add a lot of overhead to the server, especially
> >memory, I would rather suggest to first autenticate and then negociate
> >compression. I imagine a trivial attact: simply open a lot of
> >connections to a jabber server, negociate compression and go to sleep.
> >Each connection can eat easily 500 Kbytes. 1000 connections eats 500
> >Megabytes.
> Good point. In fact the server probably should not even advertise the 
> compression feature until after authentication...

IMHO that could be a deployment source. Some may want to compress all
the SASL data, when the bandwith is expensive. The <stream:features/>
element may occur before and after SASL, so why not allow using
compression in those two places? Announcing compression when it is
already in use should be forbidden only.


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