[HECnet] Connections?

[Mark Pizzolato]

Mark,

I’ve seen no evidence that anything has changed at all on Linux or other operating systems.   Changes have been made within simh to better support some situations where bridges are used, but some sort of bridge setup needs to be done like it did long ago.

Please point at specifics of what you are seeing that now allows telnet to an emulator’s IP address without setting up some sort of bridging.


-          Mark

From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE] On Behalf Of Mark Abene
Sent: Saturday, May 5, 2018 3:57 PM
To: hecnet at update.uu.se
Subject: Re: [HECnet] Connections?

Nothing of the sort. I'm saying that in the past, you couldn't telnet to an emulator's IP address from within the same host server. Naturally the host server has multiple IPs for all the emulated guest OSes. This was a well known and well documented peculiarity of BSD and Linux when logged into a shell on the host server. It's no longer the case on more recent Linux systems.

-Mark


On Sat, May 5, 2018, 10:56 AM Mark Pizzolato <Mark at infocomm.com<mailto:Mark at infocomm.com>> wrote:
Hi Mark,

I’m not understanding what you saying here.

Are you suggesting that on a single host system, you’ve got multiple independent simulators running which all are using the same IP address as the host system? And, if true these devices can then, not only uniquely communicate with remote systems (on the Internet say), and also to each other AND the host system?


-          Mark

From: owner-hecnet at Update.UU.SE<mailto:owner-hecnet at Update.UU.SE> [mailto:owner-hecnet at Update.UU.SE<mailto:owner-hecnet at Update.UU.SE>] On Behalf Of Mark Abene
Sent: Saturday, May 5, 2018 10:45 AM
To: hecnet at update.uu.se<mailto:hecnet at update.uu.se>
Subject: Re: [HECnet] Connections?

This is an often misunderstood generalization, with some people able and others not. I remember this being true on *BSD. You could not connect to a simulated IP on the same host. It *used* to also be true on Linux, but is no longer the case for some time. On my ubuntu server where I run dynamips, simh, and klh10, all on bridged taps, I can telnet to all instances, even locally.

-Mark



On Sat, May 5, 2018, 12:27 AM Johnny Billquist <bqt at softjar.se<mailto:bqt at softjar.se>> wrote:
On 2018-05-05 03:39, Robert Armstrong wrote:
>>since once Multinet grabs the interface, I can’t get to the underlying
> host.
>
>    Actually I think it’s a limitation in simh and the pcap library – the
> simh guest OS can’t talk to the host OS on the same interface.  You can
> work around the problem with a TAP device.  Check the archives for the
> simh mailing list – it’s been discussed many times before.

No. That is not correct. I run simh myself on a machine where I have
both the native host and simh talking on the same ethernet. And they are
both reachable by other hosts.
The OP must be doing something else funny.

   Johnny

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