Messages in this thread | | | Subject | Re: Linux 2.4.27 SECURITY BUG - TCP Local and REMOTE(verified) Denial of Service Attack | From | Florian Weimer <> | Date | Tue, 21 Sep 2004 22:04:41 +0200 |
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* David S. Miller:
> On Tue, 21 Sep 2004 20:32:12 +0200 > Florian Weimer <fw@deneb.enyo.de> wrote: > >> > But then you get PMTU problems... >> >> PMTU discovery is not an issue because it's turned off anyway, at >> least by default. > > It's on by default, for both TCP and UDP in the kernel, > and has been so for a long time.
Linux is not the reference TCP/IP stack for routers. 8-)
> Why would it be off by default?
Probably because PMTUD is just a DRAFT STANDARD, and these router folks are usually extremely conservative. Switching the default is dangerous because it's likely to break existing setups, as Herbert noted.
> If you disable PMTU discovery, say goodbye to TCP performance.
Indeed. On those platforms, the CPU impact is also significant, and the overall increase in BGP convergence time is measurable. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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