SYN spoofing

Vijay Gill wrath at
Wed Jul 28 17:58:03 UTC 1999

On Wed, 28 Jul 1999, Greg A. Woods wrote:

> [ On Wednesday, July 28, 1999 at 11:21:35 (-0400), Daniel Senie wrote: ]
> > Subject: Re: SYN spoofing

> In fact it's easy to buy off-the-shelf hardware today that can do
> wire-speed filtering, assuming one has worked such costs into the budget
> of building a network backbone....

It is possible to do access filtering on the edges.  Then comes the
operational aspects of actually making such a thing scale across many many
edge devices, especially when there are customers with their own space,
and who may have customers behind them with _their_ own space.  If a
promising local isp is providing transit to a bunch of other local isps,
changing every access-list on every edge node every time one of the
customer isp's adds or deletes a customer, becomes a logistical nightmare.

Some promising local isp's are then faced with blowing out huge
access-lists virtually every hour of the day, and this becomes harder to
manage when you take into accounts and now you have several tens of
promising local isps all trying to match access-lists all around.  Not to
mention the actual physical limits on current hardware regarding the size
of configurations. 


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