[systemd-devel] systemd-networkd bridge doesn't work until switched to promiscous mode

[Lennart Poettering]

On Wed, 11.02.15 17:48, Peter Lemenkov (lemenkov at gmail.com) wrote:

> Hello All!
> I see that promiscous mode was discussed a few times before but I'm
> not sure if I found something new or not.
> 
> I've got the following setup - a physical interface (enp1s0f0), which
> I wanted to add to the bridge (br0).
> 
> My setup consists of the following files
> 
> * br0.netdev:
> 
> [NetDev]
> Name=br0
> Kind=bridge
> 
> * br0.network:
> 
> [Match]
> Name=br0
> 
> [Network]
> Address=xx.yy.zz.27/27
> Gateway=xx.yy.zz.17
> 
> * enp1s0f0.network:
> 
> [Match]
> Name=enp1s0f0
> 
> [Network]
> Bridge=br0
> 
> So this looks pretty simple. Unfortunately it doesn't work.
> 
> If I start pinging xx.yy.zz.17, then I see (using tcpdump) that the
> gateway even replies, and this reply was received at physical
> interface but br0 doesn't recognize it (and consequently ping didn't
> get a reply back).
> 
> But if I change the br0 mode with "ifconfig br0 promisc" it starts
> receiving data.
> 
> Is this a known issue? Or maybe I missed something in docs?

Sounds like a kernel bug. Normally the bridge logic should turn on
promisc mode automatically if this is needed. If this doesn't work
this appears to be a kernel bug. 

That said, Tom might know more. Tom?

Lennart

-- 
Lennart Poettering, Red Hat