Re: Linux 2.4.27 SECURITY BUG - TCP Local and REMOTE(verified) Denial of Service Attack

Willy Tarreau
2004-09-13T04:19:10Z

On Mon, Sep 13, 2004 at 04:30:36AM +0100, Paul Jakma wrote:

> More specifically, BGP should have treated TCP resets as a transient
> error, to be expected (indeed, they /cant/ be a sign that a link is
> down - if you can receive a RST the link or path is patently quite
> ok).

The application level does not always distinguish between TCP RST and
error generated by the local system because of a "network unreachable"
due to a link down and a lost route.

> The BGP state machine should instead, in normal operation, have
> only treated Hold time expired as the definitive sign of "peer is
> down" and allowed reconnects.

It should not necessarily wait for the time-out, but at least wait for
a few reconnect errors.

Regards,
willy