discussion: Enabling IPv6 on Cisco 6500/7600 breaks IPv4 Internet connectivity

Jared Mauch jared at puck.nether.net
Tue Jun 26 16:27:27 CEST 2012

On Jun 26, 2012, at 10:24 AM, Bernhard Schmidt wrote:

> Am 26.06.2012 16:10, schrieb Jared Mauch:
>> I'm once again reminded of something I observed.  Make sure you
>> disable ipv6 redirects on all interfaces.  This has significant
>> performance penalty.  On 6500/sup720 this should be easy to do with
>> interface range command.
> Funky. Is this only the case with non-standard configurations like
> multiple subnets on one interface?

No.  It was odd and I didn't collect too much data on this.  It led me
to push back against those at vendors who didn't view redirects as harmful.

Its easier to just forward/recirc the packet.  I wonder if this was related
to the performance hit observed.

- Jared

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