As an ISP'll end up with collisions with their customers if RFC1918 space is used for their intermediary/ISP portion of NAT444, a new /10 (specifically 100.64.0.0/10) was allocated for this use. RFC6598 details the allocation, and the use cases for it. -- Neil Fenemor | +64 21 978 078 | Facetime | Skype On 27 February 2014 at 12:00:57 pm, Dave Mill (davemill(a)gmail.com) wrote: As a slightly more serious reply (though Mike's URL did work surprisingly well..) I would assume we are going to see more and more RFC1918 addresses used by ISPs as IPv4 runs out and CGN is used more. I'm aware of at least 3 ISPs in NZ doing this (we're one of them to some extent with a couple of our prepay products) and I'd expect there are more. Cheers Dave On Thu, Feb 27, 2014 at 11:55 AM, Mike Cooper <mikec.cooper(a)gmail.com> wrote: http://lmgtfy.com/?q=What%27s+the+BCP%2FRFC+that+says+that+routers+within+an... HTH On Thu, Feb 27, 2014 at 11:51 AM, Matt Grant <matt(a)mattgrant.net.nz> wrote: Hi! Know I am some small fry on the list, but your help would be appreciated. This would be useful in talking to my ISP about some PMTU issues that I am having re a VPN going over PPPoE, with MTU 1480. Thanks! Matt Grant _______________________________________________ NZNOG mailing list NZNOG(a)list.waikato.ac.nz http://list.waikato.ac.nz/mailman/listinfo/nznog _______________________________________________ NZNOG mailing list NZNOG(a)list.waikato.ac.nz http://list.waikato.ac.nz/mailman/listinfo/nznog _______________________________________________ NZNOG mailing list NZNOG(a)list.waikato.ac.nz http://list.waikato.ac.nz/mailman/listinfo/nznog