netdev - Re: ipv6 issues after an DDoS for kernel 4.6.3

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Date:	Fri, 8 Jul 2016 18:17:57 +0400
From:	Loganaden Velvindron <loganaden@...il.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	Toralf Förster <toralf.foerster@....de>,
	netdev <netdev@...r.kernel.org>
Subject: Re: ipv6 issues after an DDoS for kernel 4.6.3

On Fri, Jul 8, 2016 at 6:14 PM, Eric Dumazet <eric.dumazet@...il.com> wrote:
> On Fri, 2016-07-08 at 15:51 +0200, Toralf Förster wrote:
>> I do run a 4.6.3 hardened Gentoo kernel at a commodity i7 server. A
>> DDoS with about 300 MBit/sec over 5 mins resulted an issue for ipv6 at
>> that system.
>>
>> The IPv6 monitoring from my ISP told my that the to be monitored
>> services (80, 443, 52222) weren't reachable any longer at ipv6 (at
>> ipv4 there was no issue). Restarting the NIC brought back green lights
>> for the services at the ipv6 ports too.
>
> Hard to tell without knowing DDOS details, but IPv6 lacks some
> scalability improvements found in IPv4.
>
> IPv4 no longer has a routing cache, but IPv6 still has one.
>

Any pointers as to which part of the kernel to look for to implement
one for IPv6 ?


> Are you sure conntrack is needed at all ?
>
>