em0 hijacking traffic to port 623

[John Baldwin]

On Monday 21 May 2007 07:17:07 pm Jack Vogel wrote:
> On 5/21/07, Sten Spans <sten at blinkenlights.nl> wrote:
> > On Mon, 21 May 2007, Ian FREISLICH wrote:
> >
> > > Hi
> > >
> > > We've noticed an issue on our firewalls where the first em device
> > > in the system hijacks inbound port 623 tcp and udp.  The OS never
> > > sees this traffic.  Interestingly, em1 and em2 do not appear to be
> > > afflicted by this problem.  Some reading I've done points to a
> > > similar conclusion:
> > >
> > > http://blogs.sun.com/shepler/entry/port_623_or_the_mount
> > >
> > > I've looked at the bios, but I can't find any settings that remotely
> > > hint IPMI or RMCP+ or serial-over-lan.
> > >
> > > Does anyone know how I can stop the card or system from stealing
> > > port 623 in hardware or must I just stop using em0 (and/or Intel NICS)?
> >
> > Does "ifconfig em0 promisc" help ?
> > That fixed firmware related vanishing ipv6 packets on fxp and em.
> 
> Is this happening even with the latest CURRENT driver,  there is code in
> it now that is supposed to stop the firmware from doing that, at least
> that was the theory :)

We still see this at work.  We use this workaround in /etc/sysctl.conf:

net.inet.ip.portrange.lowlast=665

It seems that the em0 interface always snoops 623 looking for RCMP packets for 
IPMI (or ASF).

-- 
John Baldwin