[Simh] VAX/VMS 6.2 DECnet turned off, still resetting MAC address

[Mark Pizzolato - Info Comm]

Hi Bill,

You want VMS to not try and change the MAC address.

On Tuesday, October 20, 2015 at 1:31 PM, Bill Deegan wrote:
> I'm migrating a VMS 6.2 system from real hardware to simh VAX.
> We're running on EC2 so DECnet's a no go.

So, exactly how do you plan/want to access the simulated VAX?

What do you envision the network to look like?

> We've disabled the DECnet startup on the system, but when I turn on tracing I see:
> DBG(42740138541)+> XQ ETH: writing  dst: 02:41:0C:98:92:09  src: AA:00:04:00:20:10  proto: 0x0800  len: 98  crc: B5981F43
>
> Is there a way to enable the debugging before booting up the VAX?

The same debugging commands that enabled the above XQ debug output can certainly be put in the vax configuration file.

I'm not sure how that will help anything.

> Barring that is there a way to prevent simh catching the "setup packet" and changing the SRC MAC address?

Something in VMS is changing the MAC address on the simulated interface by issuing the appropriate I/O operations to do this.  It may be DECnet or it may also be other networking things on the system.

Before we dig into the details of that, answering the above questions about how you envision the network to look will be more helpful.

- Mark