[pim@ipng.nl: NetBSD kame - strange behavior] (fwd)

[Christian Bahls]

hope this will hit the list


---------- Forwarded message ----------
To: Pim van Pelt <pim@ipng.nl>
Subject: Re: [pim@ipng.nl: NetBSD kame - strange behavior]

this goes to 6bone(hopefully .. as i can't see any
of my previous postings regarding other topics on the list)

.. to become serious ..

hope you are familar with netstat

.. do "netstat -n -r -f inet6" (man netstat)
ignore everything that has an "R" in it (RTF_REJECT)
that are all the routes that are discarded by KAME-stack
 (good policy by itojun)

ok first one ..
fe80::%lo0/64      fe80::1%lo0        U           0        0  33220  lo0
fe80::%lo0 is routed through fe80::1%lo0 .. "Hint"
.. so next question is: what is lo0 supposed to do ?
   answer: discard packages after puting them onto the stack ..
           so every packet that gets routed to any link-lokal
           address scoped with %lo0 gets send back top your stack

.. so why can't i ping 127.0.0.2 ?, would be the next question
   answer: 127.0.0.0/8 is "REJECTED" via 127.0.0.1 which is on lo0
127                127.0.0.1          UGRS        0        2  33220  lo0
127.0.0.1          127.0.0.1          UH          6     1972  33220  lo0

.. more advanced question: why do i see my %gif0 scoped ping
                           being answered via lo0 ?
   answer: because the kernel has been told that this address is
           directly reachable by device lo0 ("U"sable+"H"ost)
fe80::201:2fe:fe10:1201%gif0       ::1      UH    0        0  33220  lo0


to make a long answer short ..
  it seems to be a policy question

and i do rather trust itojun (if it was him)
   on routing policy decisions

 christian bahls
 maths student

 university of rostock