[Oberon] Networking ETH Oberon on QEMU.

Michael Schierl schierlm at gmx.de
Mon Jul 6 22:16:18 CEST 2020

Am 06.07.2020 um 18:22 schrieb peter at easthope.ca:

> Strictly this is a QEMU question but someone here might be able to
> answer.
> This command produces error reply "qemu-system-i386: Invalid parameter 'net'".
> qemu-system-i386 -drive file=$Sysdev,format=raw \
>   -netdev tap,id=n1,ipv4=on,ipv6=off,net=,host= \
>   -device ne2k_pci,netdev=n1

You should decide if you want to use TAP networking or USER networking...

USER networking: Qemu will emulate a virtual NAT inside the guest, and
will take care of dhcp and giving the guest an IP address. The host does
not see anything in the network configuration. Like with your broadband
router, if you want to connect from host to guest, you need to add port
forwardings and connect to your host's IP address. Easy to set up, does
not require root, and you don't have to reconfigure your host. But doing
anything but TCP and UDP is tricky (like if you want to do NetBEUI or
IPX for old DOS games...)

TAP networking: Qemu will emulate a network adapter which also appears
on the host. You cannot configure any IPs etc. in qemu, as Qemu does not
care about IP (it does not even care that you speak TCP/IP over it). So
you have to configure the IP of your guest and host manually (via OS
settings). So this is more flexible, but also more work to set up. If
your guest needs a DHCP server, you have to run one on your host.

To use tap networking, you just need to give

-netdev tap,id=n1

and configure all the rest on the newly appearing TAP device.

> Therefore try this.  The intention is qemu host and qemu
> guest  (Note the ambiguity of "host".)

Then you want netdev=user and host= and dhcpstart=
(in case you want the IP assigned via DHCP).

> Has anyone made a network connection with Oberon on QEMU? Ideas?

What Oberon version exactly? A few years ago, I was able to set up
networking on ETH Native Oberon (not on qemu though), but I could not
use the built-in networking (various 3com cards supported only) as those
cards are not emulated by VirtualBox (which I used instead of qemu).
Instead I used a PPP link via virtual serial port connected to a second
VM running Linux and pppd. That Linux VM had a virtual network nic
attached and was set up to forward the IP traffic. That same setup
should work on QEMU, too (and if your host is Linux, you can probably
skip the Linux VM and run pppd directly on it).

I don't know what network cards are supported by QEMU, but I am pretty
sure that the NE2000 network driver selected by your command line is not
supported by ETH Native Oberon...



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