On 2013/03/13 18:12, Mark Martinec wrote: > Schrodinger wrote: > > What I am confused about is that without ACCEPT_RTADV on re0, FreeBSD > > doesn't perform Neighbour Solicitation for the default gateway but with > > ACCEPT_RTADV it does ..... Why ? This is Neighbour Solicitation and not > > Router Solicitation.... > > > > I understand that FreeBSD doesn't consider the defaulte gateway to be > > "on-link" so it does not perform ND for it but why does it perform ND > > when ACCEPT_RTADV is set on re0 ? "Surely" ACCEPT_RTADV only affects > > Router Advertisements / Solicitations and not ND. > > > > I have done packet captures and with ACCEPT_RTADV I see the initial > > Neighbour Solicitation and the Neighbour Advertisement to and from my > > default gateway. > > > > Without ACCEPT_RTADV - FreeBSD simply doesn't try to perform ND for the > > address. This is where I am uncertain if this is expected or not. > > That is a good question and I'd be interested in an answer too. >
Great!!! It's not just me then. > Perhaps FreeBSD is implementing a predecessor to RFC 4861, > i.e. the now obsolete RFC 2461: > > > RFC 4861, Appendix F: Changes from RFC 2461 > o Removed the on-link assumption in Section 5.2 based on RFC 4943, > "IPv6 Neighbor Discovery On-Link Assumption Considered Harmful". > > > RFC 4943, Abstract > This document describes the historical and background information > behind the removal of the "on-link assumption" from the conceptual > host sending algorithm defined in Neighbor Discovery for IP Version 6 > (IPv6). According to the algorithm as originally described, when a > host's default router list is empty, the host assumes that all > destinations are on-link. > Based on what is documented in RFC 4943 is FreeBSD not working as expected ? Since it does not perform ND for the default gateway because it isn't seen as on-link and FreeBSD is not making the on-link assumption? Correct? If I understand how FreeBSD should behave if applying RFC2461 when there is no default gateway configured it should assume the detination is on-link. Correct? I removed the default gateway, but left the interface host route for the default gateway address in the routing table and I still get "Operation not permitted" when I attempt to ping the address. # netstat -rn -f inet6 | fgrep ff:ff default 2001:41d0:2:e7ff:ff:ff:ff:ff UGS re0 2001:41d0:2:e7ff:ff:ff:ff:ff e0:69:95:88:0b:27 UHS re0 # ping6 -c 1 2001:41d0:2:e7ff:ff:ff:ff:ff PING6(56=40+8+8 bytes) 2001:41d0:2:e7c4::1 --> 2001:41d0:2:e7ff:ff:ff:ff:ff ping6: sendmsg: Operation not permitted ping6: wrote 2001:41d0:2:e7ff:ff:ff:ff:ff 16 chars, ret=-1 --- 2001:41d0:2:e7ff:ff:ff:ff:ff ping6 statistics --- 1 packets transmitted, 0 packets received, 100.0% packet loss # route delete -inet6 default delete net default # netstat -rn -f inet6 | fgrep ff:ff 2001:41d0:2:e7ff:ff:ff:ff:ff e0:69:95:88:0b:27 UHS re0 # ndp -c 2001:41d0:2:e7c4::1 (2001:41d0:2:e7c4::1) deleted fe80::e269:95ff:fe88:b27%re0 (fe80::e269:95ff:fe88:b27%re0) deleted # ping6 -c 1 2001:41d0:2:e7ff:ff:ff:ff:ff PING6(56=40+8+8 bytes) 2001:41d0:2:e7c4::1 --> 2001:41d0:2:e7ff:ff:ff:ff:ff ping6: sendmsg: Operation not permitted ping6: wrote 2001:41d0:2:e7ff:ff:ff:ff:ff 16 chars, ret=-1 --- 2001:41d0:2:e7ff:ff:ff:ff:ff ping6 statistics --- 1 packets transmitted, 0 packets received, 100.0% packet loss Although this still does not immediately explain to me why ACCEPT_RTADV causes it to perform ND. Cheers, C. -- +---------------------------------------------------------------+ Quidquid latine dictum sit, altum sonatur. MSN: sch...@hotmail.com ICQ: 112562229 GPG: http://www.konundrum.org/schro.asc
pgpCaGM_qhayJ.pgp
Description: PGP signature
