[Simh] Hello and a noobish question about networking

[Brad Parker]

Note: this is just my ranting as a user.  It's not anything official
about how simh does or does not work.

Michael Kerpan wrote:
>how do I get Simh 3.8 set up to use a tun/tap network interface in Linux?

I can only speak from my experience. I found with newer linuxes I had to
slightly modify either the code or the Makefile to get it to build with
libpcap, but the mods were trivial.

Once compiled, I always run into the classic tun/tap/linux problem -
packets sent via tun can not be "heard" by the same machine.  No doubt
googling will find me complaining about this 3-4 times over the past 18
years.

So, I just run as root and use the network interface to talk to any
other machine on the network except the machine I'm on.  This is fine
since I have several nfs servers.    And it seems to work reliably.

There are more complex setups, generally involving having an extra
ethernet card and/or using linux bridging.  I find these somewhat
fragile and a pain to work with.  Others may have different opinions
(and I'd like to hear them).

I use (for a vax780)

  set xu enabled
  att xu eth0

But, something tells me I could ifconfig the tun0 interface with a made
up network # and then config my simulation (i.e. inside vms or unix) to
be on the same network and then communicate with *only* the host linux
box.  At least I've done with other tun/tap style connections on other
emulators.  But I don't think I've ever tried it with simh.

-brad