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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">It won’t hurt your SIMH VAX to have a published “Decnet-like” MAC address of aa-00-04-00-20-10, unless there is a MAC collision on the local LAN segment. It’s
just a MAC address after all.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Any decnet protocol packets that are sent out will be ignored (dropped) by the local IP router as unroutable.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Any IP packets will route in/out to the currently set MAC address *<b>unless</b>* you’re trying to run this connection over wireless Ethernet which is a whole
different story..<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">If you are having MAC collision problems, you can also change the “fake” decnet address to another “fake” decnet address which doesn’t collide.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">If you want to get back to the “hard assigned” 08-00-2b-aa-bb-cc MAC address, you can deinstall the DECNET package from your installation, OR stop decnet from
running on system startup (to stop the decnet setup packet) .<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">You can also fix this by modifying the system parameters with an interactive boot and write, but I forget the details.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Dave<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Simh [mailto:simh-bounces@trailing-edge.com]
<b>On Behalf Of </b>Bill Deegan<br>
<b>Sent:</b> Tuesday, October 20, 2015 4:31 PM<br>
<b>To:</b> simh@trailing-edge.com<br>
<b>Subject:</b> EXT :[Simh] VAX/VMS 6.2 DECnet turned off, still resetting MAC address<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">Greetings,<o:p></o:p></p>
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<p class="MsoNormal">I'm migrating a VMS 6.2 system from real hardware to simh VAX.<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">We're running on EC2 so DECnet's a no go.<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">We've disabled the DECnet startup on the system, but when I turn on tracing I see:<br>
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<o:p></o:p></p>
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<p class="MsoNormal">Is there a way to enable the debugging before booting up the VAX?<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">Barring that is there a way to prevent simh catching the "setup packet" and changing the SRC MAC address?<o:p></o:p></p>
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<p class="MsoNormal">-Bill<o:p></o:p></p>
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