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Re: default route on other subnet
Quoting Jean-Yves Migeon 01/07/2011 00:29,
What you are trying to achieve is kind of difficult. With a xennet0
configured as a /32 in domU (and without a default route), you are
basically setting up your domain as being "non routable". It can only
communicate with itself (excluding certain circumstances, but that's not
the point here).
sorry for coming back on that matter, but that's exactly the point.
That's even the subject of this thread: using a default route on another
subnet. Do you really think that it's the /32 netmask that prevents the
route trick to work? I tryed again today with current and on a brand
new linux dom0; and it's a very standard XEN configuration. In fact,
I'm always building the whole thing from scratch with the official
tarball for xen & tools (4.1.1), and jeremy's repository (today's
next-2.6.32). The same happens again.
In a basic bridge configuration, with a reachable gateway on network
interface, this is supposed to do the trick on the netbsd guest side,
ifconfig xennet0 GUESTIP netmask 255.255.255.255 up
route add -host GATEWAYIP -link xennet0 -iface
route add default -ifa GUESTIP GATEWAYIP
but instead I still receive the arp warnings (xx:xx:xx:xx:xx:xx tried to
overwrite permanent arp info for GATEWAYIP).
Routing packets (like the ones with your ping) will only work when the
domain is capable of figuring out a route at a L2 level, e.g. AF_LINK
for routing socket. But the NetBSD domain will refuse to add addresses
in its ARP table that do not belong to its networks, and as it has none...
I tryed with network 255.255.0.0 instead, trying to overcome what you
just said, while keeping the rest of the procedure (route add -host and
default). No changes, I still receive the happy arp warnings.
For routing dom0 <> domU, without proxy ARP, I'd suggest to set an IP
for vif, and a small iproute2 command:
Now about a routing configuration, without proxy ARP (I honestly don't
know what it is about anyway), I have to use an additional IP indeed,
which isn't an option here as I'm dealing with public IPs (and I don't
have much of them).
Of course the problem would be solved if I could use NAT. Thing is, I'm
fighting, for a few monthes now, because I precisely would like NetBSD
to be my nat gateway for the other guests. I can't stand iptables and
appreciate the good old ipfilter & ipnat tools.
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