[9fans] two nics (alternating) vs dns config

[Troy Cauble]

I have plan9 in VirtualBox on a macbook.
I use the wired network at work and wifi at home.
The Vbox config has two network adaptors,
1 bridged to the wired and 1 bridged to the wifi.

I'd like my plan9 config to boot and work on either network.
(Even better if it could switch without a reboot!)

I've bound '#l1' to /net (not /net.alt) in /lib/namespace.$node
and /cfg/$node/cpurc. The two static ipconfigs work.
I can ping out and drawterm in.

The only issue is dns. DNS always uses /net/ether0.
How do I make it use /net/ether1 when needed?
Would the /net.alt style config work better?

My /lib/ndb/local describes both networks with the same sys name.
MAC addresses differentiate. 'ndb/query sys $node' returns the
right set when I'm home, but DNS doesn't use it.

Thanks,
-troy

[Henning Schild]

I suggest you give your VM one NAT interface and run a DNS server on
your macbook. That way you can completely hide mobility from plan9,
which is a good idea because it can not really handle it.
You can also restart the dns resolver telling it which server to use
(/env/DNSSERVER) but that will not affect running processes. I guess
dns should provide a ctl file to allow reconfiguration at runtime.
For your special case you can put multiple ips in /env/DNSSERVER, on
your secondary network you will have to wait until the primary times
out but it will work.

Henning

On Tue, 24 Jan 2012 05:15:20 +0100

Post by Troy Cauble
I have plan9 in VirtualBox on a macbook.
I use the wired network at work and wifi at home.
The Vbox config has two network adaptors,
1 bridged to the wired and 1 bridged to the wifi.
I'd like my plan9 config to boot and work on either network.
(Even better if it could switch without a reboot!)
I've bound '#l1' to /net (not /net.alt) in /lib/namespace.$node
and /cfg/$node/cpurc. The two static ipconfigs work.
I can ping out and drawterm in.
The only issue is dns. DNS always uses /net/ether0.
How do I make it use /net/ether1 when needed?
Would the /net.alt style config work better?
My /lib/ndb/local describes both networks with the same sys name.
MAC addresses differentiate. 'ndb/query sys $node' returns the
right set when I'm home, but DNS doesn't use it.
Thanks,
-troy

[Charles Forsyth]

there is one, but it doesn't seem to be documented.

echo refresh >/net/dns
# or you can escalate to
echo restart >/net/dns
# but then you might need to remount in some name spaces

Post by Henning Schild
I guess
dns should provide a ctl file to allow reconfiguration at runtime.

[Steve Simon]

You could always use googl'es DNS server if local conditions (firewalls) permit.

8.8.8.8 and 8.8.4.4

-Steve