ISP customer assignments

Wed Oct 14 00:36:39 UTC 2009

That was the point.  :)

Scott

Matthew Petach wrote:
>
>
> On Mon, Oct 12, 2009 at 8:32 PM, Scott Morris <swm at emanon.com
> <mailto:swm at emanon.com>> wrote:
>
>     How many addresses do you like on point-to-point circuits?
>
>     Scott
>
>
> I allocate a /64, but currently I configure only a /127 subnet on the
> actual interface.  That prevents the neighbor table explosion/NS/ND
> traffic flooding challenges that can occur otherwise if you configure
> the link as a /64, and some not-nice person decides to start ping
> sweeping or nmapping the subnet; your router has to send out NS
> messages for every address in the /64 being probed, update the
> neighbor table with the incomplete entry, then flush it out when
> no ND message is seen.  On a point-to-point link between
> routers you're never going to run stateless autoconfiguration,
> so there's not much downside to configuring it as a /127.
>
> Still...just in case, I do allocate the whole /64 for the link, so
> that if in the future it turns out that for some reason it really,
> *really* does have to be a /64 configured on it, I can make the
> change just by adjusting masks on each end, rather than
> having to actually renumber the entire network.
>
> *shrug*  As always, your mileage will vary, but this has
> worked out well for me so far.
>
> Matt
>