nanog mailing list archives
Re: ISP customer assignments
From: Matthew Petach <mpetach () netflight com>
Date: Tue, 13 Oct 2009 11:46:39 -0700
On Mon, Oct 12, 2009 at 8:32 PM, Scott Morris <swm () 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
Current thread:
- Re: ISP customer assignments, (continued)
- Re: ISP customer assignments Scott Morris (Oct 13)
- Re: ISP customer assignments John Kristoff (Oct 13)
- Re: ISP customer assignments TJ (Oct 13)
- Re: ISP customer assignments Daniel Golding (Oct 16)
- RE: ISP customer assignments Brian Johnson (Oct 16)
- Re: ISP customer assignments Walter Keen (Oct 16)
- Re: ISP customer assignments Owen DeLong (Oct 16)
- Re: ISP customer assignments - and CIDR James R. Cutler (Oct 16)
- Re: ISP customer assignments Valdis . Kletnieks (Oct 13)
- Re: ISP customer assignments Mark Smith (Oct 13)
- Re: ISP customer assignments Matthew Petach (Oct 13)
- Re: ISP customer assignments Joe Abley (Oct 13)
- Re: ISP customer assignments Marco Hogewoning (Oct 13)
- Re: ISP customer assignments Scott Morris (Oct 13)
- Re: ISP customer assignments Michael Dillon (Oct 13)
- Re: ISP customer assignments Chris Adams (Oct 13)
- Re: ISP customer assignments Cord MacLeod (Oct 13)
- Re: ISP customer assignments James Hess (Oct 13)
- Re: ISP customer assignments Kevin Loch (Oct 13)
- Re: ISP customer assignments Leo Bicknell (Oct 13)
- Re: ISP customer assignments Chris Adams (Oct 13)