[CentOS-virt] KVM networking issue
Mike - st257
silvertip257 at gmail.com
Fri Mar 25 16:45:01 UTC 2016
On Thu, Mar 24, 2016 at 4:30 PM, Kevin Ross <sedecim at gmail.com> wrote:
> Thanks, Mike. When running tcpdump on the VM I'm not seeing traffic
> unless it's explicitly intended for that particular VM, so no traffic
> between the other VMs is getting forwarded from the virtual interface
> to the "network appliance" VM.
> There is connectivity between the VMs on the private network and the
> "network appliance" VM which is acting as a gateway.
> Here's the output of the brctl command:
> bridge id 8000.5254007e2f5b
> designated root 8000.5254007e2f5b
> root port 0 path cost
> max age 19.99 bridge max age
> hello time 1.99 bridge hello time
> forward delay 0.00 bridge forward delay
> ageing time 299.95
> hello timer 0.29 tcn timer
> topology change timer 0.00 gc timer
> hash elasticity 4 hash max
> mc last member count 2 mc init query count
> mc router 1 mc snooping
> mc last member timer 0.99 mc membership timer
> mc querier timer 254.96 mc query interval
> mc response interval 9.99 mc init query interval
> virbr1-nic (0)
> port id 0000 state
> designated root 8000.5254007e2f5b path cost
> designated bridge 8000.5254007e2f5b message age timer
> designated port 8001 forward delay timer
> designated cost 0 hold timer
> mc router 1
> I'm not sure why virbr1-nic is showing up as disabled, and also why
That STP output says the virbr1-nic interface is disabled -- maybe your VM
is powered off?
> the vnet# interfaces don't show up (they do show up on another host,
> although VMs on that host are having the same non-promiscuous issue as
> these VMs). I've tried this with and without NAT, as well as with STP
> on/off with no effect.
You'll need to enable IP forwarding and set rules to route the traffic for
The gotcha is that if you're not doing any IP routing on the KVM node, your
"network appliance" VM needs to have one NIC bridged to your real network
and the other as part of virbr1. You could NAT it on the KVM host as well.
Read the KVM networking documentation as it will help you determine what
configuration you have and if that's what you want.
// SilverTip257 //
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