Re: [Asrg] DNSBL and IPv6

Paul Smith <paul@pscs.co.uk> Thu, 25 October 2012 16:40 UTC

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Subject: Re: [Asrg] DNSBL and IPv6
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On 25/10/2012 17:10, Emanuele Balla (aka Skull) wrote:
>> Hmm - I've heard talk about this problem of saturating the router
>> neighbour table. To be honest, I'm not entirely sure what a 'neighbour
>> table' is...
> Basically, the ARP table, except for IPv6 not using ARP at all...
OK. I know what an ARP table is :-)

The name 'neighbour table' made me think it was trying to track which 
other routers were around (ie 'neighbours' of this router), which was 
strange if that got upset by the number of internal addresses being 
used. My mental visualisation sees the router as a 'gatekeeper', so the 
internal devices would be 'occupants' or something, not 'neighbours'. 
So, I visualised that 'neighbours' would be things on the same 'level' 
as the router - ie other routers.

I've done a bit more reading around on the subject, and am getting there 
- I think :-)

It's tricky since we have no access to any IPv6 stuff unless I use a 
tunnel or an internal test network, which has always been an 
"artificial" environment AFAIAC (no local router involved), so doing 
full scale real-world tests isn't possible yet.

> The router basically needs to cope with a given number of devices inside
> the /64. Maybe 10, maybe 100, maybe 1000, but a limited amount, compared
> to 2^64. The neighbor table must be able to keep track of IPv6-MAC
> associations for each device.
OK



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