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><A
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></A
>6. FAQ</H1
><P
></P
><OL
TYPE="1"
><LI
><P
><EM
>Q: Why do we have to create the
<TT
CLASS="filename"
>/dev/mipv6_dev</TT
> entry?</EM
></P
><P
>A: The dev file is mainly so that the userspace tool,
mipdiag, can make modifications to the kernel parameters using
ioctl calls through the device file. <B
CLASS="command"
>mknod</B
> creates the special
device file with paramters recognizable by the mobile-ip6
module.</P
></LI
><LI
><P
><EM
>Q: Is there any support for kernel 2.6.x?</EM
></P
><P
>A: Here is the<A
HREF="http://www.mobile-ipv6.org/pipermail/mipl/2003-December/001871.html"
TARGET="_top"
> answer from Henrik Petander</A
> on the MIPL
mailinglist:</P
><P
><SPAN
CLASS="QUOTE"
>"Here is a short overview of the status of MIPL for
2.6 kernel series:"</SPAN
></P
><P
><SPAN
CLASS="QUOTE"
>"We have finished the kernel infrastructure for
Mobile IPv6 in cooperation with the USAGI project. The
infrastructure does route optimization, tunneling and policy
routing."</SPAN
></P
><P
><SPAN
CLASS="QUOTE"
>"We are now working on the userspace daemon which
handles the MIPv6 signaling and controls the operation of the
kernel part. The userspace part is also progressing
nicely. However, the protocol logic is still missing, so there
isn't really anything for users to test yet. We should have a
well working and tested prototype ready and by the end of
March."</SPAN
></P
></LI
><LI
><P
><EM
>Q: Does MIPL support
IPSec?</EM
></P
><P
>A: There is no support IPSec on 2.4.x. MIPL for 2.6 series will
have IPSec support from the start. You may use a third-party IPSec
implementation.</P
></LI
><LI
><P
><EM
>Q: How can I control the type of routing used for
communication between the MN and a CN (through HA tunnel or by
direct communication using binding update/acks)?</EM
></P
><P
>A: You can control this through:</P
><P
> <TT
CLASS="userinput"
><B
>/proc/sys/conf/net/ipv6/mobility/accept_return_routability</B
></TT
>
</P
><P
>If you do not want to use return routability and route optimization,
set it to 0 with:</P
><P
> <TT
CLASS="userinput"
><B
># echo 0 >
/proc/sys/..../accept_return_routability</B
></TT
>
</P
><P
> Then MN will communicate with CNs only through the
home tunnel.</P
></LI
><LI
><P
><EM
>Q: Can different wireless networks
have different ESSIDs/WEP keys?</EM
></P
><P
>A: Yes, but you must change this upon arrival to the new
network. MIPv6 from MIPL can't do this automatically.</P
></LI
><LI
><P
><EM
>Q: If MN has travelled through several visited
LAN, and then returning home; the interface still has all the
autogenerated IPv6 addresses from all the visited networks! Is
there any way to <SPAN
CLASS="QUOTE"
>"flush/delete"</SPAN
> these
addresses?</EM
></P
><P
>A: No, I do not know of any automatic way these adresses
can be removed, but you can delete them manually:</P
><P
><TT
CLASS="userinput"
><B
> # ifconfig eth0 inet6 del <ipv6-address>
</B
></TT
></P
></LI
><LI
><P
><EM
>Q: Host B has two interfaces with two
different subnets assigned. When I ping B from host A, it does
not answer! Why not? Host A knows where host B
(subnets) are!</EM
></P
><P
>A: The host B doesn't know where host A is (B doesn't
know where A's net is), so you must add a route
entry:</P
><P
><TT
CLASS="userinput"
><B
> # ip route add fec0:106:2700::/64 via fec0:106:2300::1
</B
></TT
></P
><P
>or</P
><P
><TT
CLASS="userinput"
><B
> # route -A inet6 add fec0:106:2700::/64 gw fec0:106:2300::1 dev eth0
</B
></TT
></P
></LI
><LI
><P
><EM
>Q: How do I set a default gateway in
IPv6?</EM
></P
><P
>A: You do that using the traditional <SPAN
CLASS="QUOTE"
>"route"</SPAN
>:</P
><P
><TT
CLASS="userinput"
><B
> # route -A inet6 add default gw <ipv6-host>
</B
></TT
></P
><P
>or the newer <SPAN
CLASS="QUOTE"
>"ip"</SPAN
> command:</P
><P
><TT
CLASS="userinput"
><B
> # ip route ::/0 via <ipv6-host>
</B
></TT
></P
></LI
><LI
><P
><EM
>Q: Why does the host send a multicast
address rather than an anycast address, requesting for router
solicitation?</EM
></P
><P
>A: Because the host wants an answer from every router, not from just any
router. The idea is to be able to get all parameters and to choose
the <SPAN
CLASS="QUOTE"
>"best"</SPAN
> default router.</P
></LI
><LI
><P
><EM
>Q: Why doesn't MN notice that it has
moved?</EM
></P
><P
>A: It thinks that it's previous router is still reachable. This may
result from very large lifetimes in router advertisements. Check the
configuration of the program sending router advertisements in the
router. If the program supports router advertisement intervals, you
can use this to help MN in movement detection by setting the use of
interval to <TT
CLASS="option"
>on</TT
>. See <B
CLASS="command"
>man radvd.conf</B
> for
details.</P
></LI
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