Messages in this thread | | | From | (David Wagner) | Subject | Re: ack number in a connection-refused RST | Date | 6 Oct 2000 21:34:35 GMT |
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Andi Kleen wrote: >On Fri, Oct 06, 2000 at 09:06:31PM +0000, David Wagner wrote: >> David S. Miller wrote: >> >Linux should not honor the incorrect sequence number. If the sequence >> >number is incorrect, the RST could legitimately be for another >> >connection. >> >> How could it be for another connection, if it has source and destination >> port numbers? > >You're missing dynamic IPs, NAT and reboot of hosts.
Ok, but with dynamic IP, NAT, and reboots, you can also get incorrect results with today's implementation, if you see a RST with the correct sequence number (not the off-by-one incorrect one). It's just a probabilistic argument that this is unlikely to happen in practice -- namely, it only happens with probability 1/2^32 (you hope).
There's no fundamental reason why you couldn't accept off-by-one sequence numbers as well, if it was deemed important for interoperability; the probability would just increase to 1/2^31, which is still small (albeit not as small as 1/2^32).
Right? Or am I still missing something? I'm not a TCP expert. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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