[Simh] Klh10 vs Simh

[Johnny Billquist]

On 2016-02-27 20:14, Andreas Davour wrote:
> On Sat, 27 Feb 2016, Johnny Billquist wrote:
>
>> On 2016-02-27 17:53, Michael Kerpan wrote:
>>> It's not that multiuser is impossible using KLH10 networking emulation
>>> and native TOPS-20 TCP/IP, it's that it's a lot harder to set up than a
>>> SIMH virtual multiplexer. Wifi (under Linux at least) doesn't play all
>>> that well with bridging and virtual networking stuff, which makes
>>> setting up networking in KLH10 nigh impossible for those of us stuck on
>>> wireless. I can't even really set up a VM and run KLH10 in a guest,
>>> because Virtualbox's bridged mode doesn't work for me. Additionally, the
>>> idea of putting anything running a 30 year old TCP/IP stack onto the
>>> Internet scares me, even if the folks at twenex.org <http://twenex.org>
>>> have done so.
>>
>> The WiFi problem is easy to solve. It's called a router. Your host
>> routes IP between the WiFi interface and the virtual network the host
>> and your virtual machine shares.
>>
>> Trouble setting up networking on the virtual machine? Maybe. But this
>> boils down to - if you want to run that host, you should learn how to
>> manage it.
>>
>> Security issues are mostly non-issues. How many script kiddies today
>> even know what a TOPS-20 host is. There are most certainly
>> vulnerabilities, but they are very different from the ones presented
>> by modern machines.
>>
>> I have an RSX system on the Internet, and it gets constant probing
>> over telnet and http, but they are all probing in ways that just don't
>> make sense. So I have never felt more secure.
>
> To Johnnys suggestions I might add that (I don't know exactly what
> problems you're having) maybe openvswitch might help out?

The problem is that WiFi is not really like ethernet (I think we covered 
this a month ago, but maybe it was on a different list). Anyway, if you 
have a simh instance using WiFi for the network, it do not work, since 
putting the interface in promiscuous mode, and pretend you have a second 
machine with a different MAC address do not work, since with WiFi, the 
base station actually knows which MAC addresses are connected, and if a 
packet comes in for a device for which the MAC address is not 
registered, the packet will not be send out over WiFi, so you will not 
get anything, even though you think you have your interface in 
promiscuous mode, and are sending packets out with a different source 
MAC address, which you might think the WiFi switch would learn, as it 
would had it been ethernet.

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol