[Simh] SimH networking on Ubuntu (dapper)

[Mark Pizzolato - Info Comm]

Let's go back to the simplest case which is with  2 NIC cards.

What you need to do in this case is:
1) The primary NIC (eth0) will be setup normally and you should be able
to ping and otherwise access nodes on the LAN.
2) The second NIC should be plugged into the SAME network as the primary
NIC.
3) The second NIC SHOULD NOT be used by the networking on the Ubuntu
system (i.e. NO IP Address explicitly assigned and none set by DHCP).
You should have to explicitly turn on that NIC with something like
"/sbin/ifconfig eth2 up"
4) The SIMH vax must be rebuilt with network support (the Ubuntu package
isn't currently built that way, we're trying to fix that for the next
SIMH release).
5) You SIMH vax should "attach xq eth2"
6) You SIMH vax should have an IP address either dynamically or
explicitly set which is on the SAME LAN as eth0 (i.e. 192.168.0.169) and
the netmask should be set consistently with respect to all of the other
hosts on that LAN.

This does work, although you'll have to be running the SIMH vax as root
to succeed in step 5+ above. 

 You can avoid the need to run the SIMH vax as root by leveraging Linux
"Filesystem Capabilities" to give the SIMH vax executable the needed
capabilities.  The article at:
http://packetlife.net/blog/2010/mar/19/sniffing-wireshark-non-root-user/
describes how to run Wireshark using Filesystem Capabilities.  The SIMH
needs the exact same capabilities as Wireshark to avoid running as root.

Clearly, since the SIMH vax is directly on the LAN, any/all network
traffic the SIMH vax generates will be available for communications with
any other hosts on that LAN (i.e. DECnet, LAVC, LAT, etc...).

Using a bridge configuration is another more complex topic.   Try to the
above first and after you have that working we'll explore the specifics
of getting the exact same functionality by using a single NIC.

- Mark Pizzolato

> -----Original Message-----
> From: simh-bounces at trailing-edge.com [mailto:simh-bounces at trailing-
> edge.com] On Behalf Of Paul Stevens
> Sent: Friday, June 11, 2010 9:54 AM
> To: simh at trailing-edge.com
> Subject: [Simh] SimH networking on Ubuntu (dapper)
> 
> I need help gettting the network portion of Simh emulating a Vax 3900
> working. I can boot the VAX with any problems with xq attaching to
what
> ever device i put in vax.ini, but from VAX or Ubuntu can not ping or
arp each
> other.
> 
> Here's my configuration;
> 
> Eth0: 192.168.0.168---My local network
> Eth2: For VAX  on 192.169.42.0
> 
> br0: Ethernet bridge 192.169.42.4
> 	eth2: 0.0.0.0 promisc up
> 	tap0: 0.0.0.0 promisc up
> 	tap3: 0.0.0.0 promisc up
> 
> Vax: ip address 192.169.42.14
> 
> I have tried just using 2 NIC cards Eth0 and Eth2 does not work.
> 
> I need to be able to telnet from and machine on the 192.168.0 network
to
> the VAX.
> 
> Router for the 192.168.0 network is 192.168.0.12
> 
> Thanks Paul
> 
> 
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