NSPs and filters (fwd)

Mon Jul 14 16:47:17 UTC 1997

On Mon, 14 Jul 1997, Daniel Senie wrote:

> And it goes beyond that... Every PC running Windows (or any other OS,
> for that matter) has complete ability to do anything with IP. So, any
> user on a dialup line into any ISP is a possible source of attacks.

Not at 1.5mbps :).  Granted I've seen effective synflooding come from a
dialup customer.  Can you say luserdel.  I think you can. :)

> This is why I think the RAS servers need to be able to filter right at
> the point of the dialup. There, the comparison is a simple compare of a
> 32 bit integer (IP address assigned to the dialup user, compared to the
> IP address of packets received from the user). Any discrepancies should
> set off alarm bells...

It's mostly that simple, but not entirely.  Filters for dialup subnet
customers would likely need to make 2 comparisons.

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