Gregg C Levine writes:
> Has anyone actually tried out IPv6 under Linux, while its running on
> an appropriate Z-Box, and his relatives?
I've tried it over the last couple of days after reading up on it again
(the last time I played with IPv6 and the 6bone was before/during the
first address bit allocation wars which dates my activity somewhat :-).
The good news is that I can set up a sit tunnel from a Linux/ia32 box
to a Linux SLES8 guest under VM and it works fine. SLES8 comes out of
the box with the basic IPv6 tools and ping6/tracepath6 work fine. That
shows the general IPv6 stuff is OK.
The bad news is that I can't get a virtual QDIO interface (i.e. on a
QDIO GuestLAN) to work with IPv6. This may well have something to do
with the fact that the kernel logs the line
qeth: IPv6 not supported on eth0
but I ploughed on regardless. This is z/VM 4.3 service level 0202
running 64-bit (second level) on a z900. The GuestLAN is type QDIO
(i.e. not HIPER) and each of two Linux guests has a virtual NIC
defined and coupled to it. They run SLES8 (I've tried with both the
shipped qeth driver and the qeth-susekernel-2.4.19-s390-1 driver
which developerworks implies is later and fixes a few bugs. One of
the bugs fixed in that claims to be "MAC address could not be
determined for VM Guest LAN interfaces" but even with the new driver
"ip link show eth0" still shows zeroes for the MAC address.
Both those drivers work fine with IPv4. As far as IPv6 is concerned,
an "ip -6 addr ls" shows
1: lo: <LOOPBACK,UP> mtu 16436 qdisc noqueue
inet6 ::1/128 scope host
3: eth0: <MULTICAST,UP> mtu 1492 qdisc pfifo_fast qlen 100
inet6 fe80::200:ff:fe00:0/10 scope link
4: tr0: <BROADCAST,MULTICAST,UP> mtu 1492 qdisc pfifo_fast qlen 100
inet6 fe80::a00:5aff:fe0c:c6aa/10 scope link
from which we can determine that the link local IPv6 address for tr0
is behaving (with the low bits correctly calculated from its MAC
address) but that the link local address for eth0 (the GuestLAN
interface) doesn't look right (especially when an "hcp q nic 7000"
shows its (faked) MAC address as 00-04-AC-00-00-00). Interestingly,
the other Linux guest (still using the original SLES8 qeth module),
shows exactly the same link local addres (oops) which led to a
short "hooray, ping6 of the other guest's IPv6 link-local address
works" before I realised that the duplicate address actually meant
it was pinging itself. Regardless of the link-local address, I tried
adding site-local addresses (fec0::2 and fec0::9) with appropriate
routes to the guests sharing the GuestLAN but although setting the
addresses and routes didn't give any errors, a ping6 from one guest
to the other just sat there (no errors; the behaviour you'd get from
packets dropped on the floor).
The latest "Device Drivers and Installation Commands" manual (for the
May 2002 stream) says about the qeth driver
Support for IPv6 applies to Gigabit Ethernet (GbE) and
Fast Ethernet (FENET) only.
which may mean "we don't support GuestLAN NICs" or may mean
"we support GuestLAN NICs because they're the virtual equivalent of
a real Gigabit Ethernet NIC". Given the ultra-concise
"qeth: IPv6 not supported on eth0" message, it's possible the former
but, unfortunately, I can't go check the code to tell.
Does anyone know any further detail for sure about IPv6 support for
QDIO (GuestLAN and otherwise)?
--Malcolm
--
Malcolm Beattie <[EMAIL PROTECTED]>
Linux Technical Consultant
IBM EMEA Enterprise Server Group...
...from home, speaking only for myself
