Re: [gentoo-user] Re: my 5.15.93 kernel keeps rebooting

[Rich Freeman]

On Thu, Feb 16, 2023 at 6:50 AM John Covici <covici@××××××××××.com> wrote:
>
> The sending computer has two nics, eno1 for the internal network and
> eno2 is on the internet.  So, my netconsole  stanza said
> netconsole=@192.168.0.1/eno1,@192.168.0.2

Is CONFIG_NETCONSOLE enabled for your kernel?

I'm not sure if the kernel will assign the names eno1/2 to interfaces
- I think those might be assigned by udev, which probably won't have
run before the kernel parses this instruction.  You might need to use
eth0/1 - and your guess is as good as mine which one corresponds to
which.

If it isn't one of those it might not hurt to put the target mac
address in there just to be safe.  I haven't needed that but maybe
there are situations where ARP won't work (it would be needed if you
are crossing subnets, in which case you'd need the gateway MAC).  Keep
in mind that this is a low-level function that doesn't use any
routing/userspace/etc.  It was designed to be robust in the event of a
PANIC and to be able to be enabled fairly early during boot, so it
can't rely on the sorts of things we just take for granted with
networking.

>
> The box which is at 192.168.0.2 has netcat (windows version) and I
> tried the following:
> netcat -u -v -l 192.168.0.2 6666 and I also tried 192.168.0.1 6666
> which is the ip address of the linux console which I am trying to
> debug.
>
> I also tried 0.0.0.0 6666 which did not work either, but I think the
> windows firewall was blocking, and I did fix that, but did not try the
> 0.0.0.0 after that.
>

So I'm pretty sure that netcat requires listing the destination IP,
since it has to open a socket to listen on that IP.  You can
optionally set a source address/port in which case it will ignore
anything else, but by default it will accept packets from any source.

I was definitely going to suggest making sure that a windows firewall
wasn't blocking the inbound connections.  That's fairly default
behavior on windows.

-- 
Rich