User manual

Linux

Then take a note of your interface and route properties in case you may want to roll back the bridging

without rebooting the system:

ifconfig >old-ifconfig.txt

route –n >old-route.txt

Make script file linux-tap.sh executable

chmod a+x linux-tap.sh

and execute it as root passing parameters for the name of tap interface to create, existing physical

Ethernet interface to use, bridge interface to create and userid of the account to own the created tap

interface and that will be used to run VAX MP, for example:

sudo ./linux-tap.sh create br0 eth0 tap0 vaxuser

Only Ethernet NICs and virtual Ethernet adapters such as TAP adapters can be attached to XQ or XQB for

mapping virtual DEQNA or DELQA adapter. Host WiFi interfaces might superficially look similar to

Ethernet interfaces but they are actually not Ethernet and cannot be used for VAX MP or SIMH Ethernet

networking.

This will create a bridge interface (br0) connecting two “slave” interfaces (tap0 and eth0). Original IP

address of Linux machine initially bound to eth0 will now be bound to br0, and Linux transport protocol

layer will be talking to br0 instead of eth0.

Attach created tap0 adapter to XQ in VAX MP startup script:

set xq enabled

set xq mac=08-00-2b-aa-bb-c1

set xq type=delqa

attach xq tap:tap0

The bridge is three-way and connects together VAX MP (via tap0), host protocol layer (via br0) and host

NIC (eth0). All Ethernet packets arriving from any one of these sources will be propagated to the other

two.

Assuming for the sake of example host IP address is 192.168.21.3, you can configure OpenVMS TCP/IP

Services interface QE0 (bound to virtual adaptor XQ) to have IP address let us say 192.168.21.200. Both

host and VAX MP can communicate with each other using target’s assigned address. They are also able

to communicate with external computers linked to eth0 (and also nodes routed to further) by these

nodes’ addresses. External hosts in turn are able to communicate with both the host machine and VAX

MP by addresses assigned to those.

Bridging association and created tap interface are lost when host system reboots. Instructions on how to roll back

the bridging without rebooting can be found further down in this section.