Re: [PATCH] [1/1] Deprecate tcp_tw_{reuse,recycle}

2008-01-31 Thread Andi Kleen
On Thu, Jan 31, 2008 at 08:41:38AM -0800, Ben Greear wrote: > I don't know exactly how the tcp_tw_recycle works, but it seems like it > could be made to only > take affect when all local ports are used up in TIME_WAIT. TIME-WAIT does not actually use up local ports; it uses up remote ports beca

Re: [PATCH] [1/1] Deprecate tcp_tw_{reuse,recycle}

2008-01-31 Thread Ben Greear
Andi Kleen wrote: I believe the problem was that all of my ports were used up with TIME_WAIT sockets and so it couldn't create more. My test case was similar to this: Ah that's simple to solve then :- use more IP addresses and bind to them in RR in your user program. Arguably the Linux

Re: [PATCH] [1/1] Deprecate tcp_tw_{reuse,recycle}

2008-01-30 Thread Andi Kleen
> I believe the problem was that all of my ports were used up with > TIME_WAIT sockets and so it couldn't create more. My test > case was similar to this: Ah that's simple to solve then :- use more IP addresses and bind to them in RR in your user program. Arguably the Linux TCP code should be

Re: [PATCH] [1/1] Deprecate tcp_tw_{reuse,recycle}

2008-01-30 Thread Ben Greear
Andi Kleen wrote: On Wednesday 30 January 2008 20:22, Ben Greear wrote: We use these features to enable creating very high numbers of short-lived TCP connections, primarily used as a test tool for other network devices. Hopefully these other network devices don't do any NAT then or do

Re: [PATCH] [1/1] Deprecate tcp_tw_{reuse,recycle}

2008-01-30 Thread Andi Kleen
On Wednesday 30 January 2008 20:22, Ben Greear wrote: > We use these features to enable creating very high numbers of short-lived > TCP connections, primarily used as a test tool for other network > devices. Hopefully these other network devices don't do any NAT then or don't otherwise violate th

Re: [PATCH] [1/1] Deprecate tcp_tw_{reuse,recycle}

2008-01-30 Thread Ben Greear
Andi Kleen wrote: We've recently had a long discussion about the CVE-2005-0356 time stamp denial-of-service attack. It turned out that Linux is only vunerable to this problem when tcp_tw_recycle is enabled (which it is not by default). In general these two options are not really usable in toda

[PATCH] [1/1] Deprecate tcp_tw_{reuse,recycle}

2008-01-30 Thread Andi Kleen
We've recently had a long discussion about the CVE-2005-0356 time stamp denial-of-service attack. It turned out that Linux is only vunerable to this problem when tcp_tw_recycle is enabled (which it is not by default). In general these two options are not really usable in today's internet becaus