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Modified MAC address still seen after DECNET removed

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Zeni B. Schleter
Regular Advisor

Modified MAC address still seen after DECNET removed

In June , I removed DECNET-Plus from a test system. I was switching to DECnet-over-IP. Multinet is the IP stack in use. All was well until recent power outage . Network connectivity was gone. Apparently up until that point the modified MAC address from its DECNet days was still broadcast.
Should the modified MAC address be getting used in the network communication now that the system is strictly IP? Does the SCSSYSTEMID need to be set back to 0 ?
If this is a well-trod road, insight would be appreciated.
9 REPLIES
Verne Britton
Regular Advisor
Solution

Re: Modified MAC address still seen after DECNET removed

Multinet says in HELP MULTI SET INTER /DECNET

MULTINET

SET_Command

/INTERFACE

/DECNET_ETHERNET_ADDRESS

/DECNET_ETHERNET_ADDRESS (default)
/NODECNET_ETHERNET_ADDRESS

Initializes a DECnet shared Ethernet interface to determine
what Ethernet address to use. If other protocols are currently
using the device, the Ethernet address cannot be changed and this
qualifier is ignored.

The default behavior, /DECNET_ETHERNET_ADDRESS, is used by
MULTINET SET/INTERFACE to look at the SCSSYSTEMID SYSGEN
parameter and set the Ethernet address to match. If SCSSYSTEMID
is not set, the address on the Ethernet card's PROM is used.

If /NODECNET_ETHERNET_ADDRESS is specified, MultiNet uses the
PROM address.

================================================

so ... I believe that means, even without DECnet being around, the default is for Multinet to assume you will use DECnet sometime in the future and it sets the MAC address ...

One way to make Multinet not do this is to use the optional user-supplied file MultiNet:se0_Configure.Com and place in that file all the required commands; one production file I have is attached ... naturally review it carefully as I have made several edits :-)

And see the Multinet example file se0_Configure.Com in the [.EXAMPLES] directory in the Multinet root.


Verne
Hoff
Honored Contributor

Re: Modified MAC address still seen after DECNET removed

Um, so?

Do you have a failure here?

Or is this curiosity?

If you have DECnet Phase IV around, it's going to set the MAC address.

It's DECnet-Plus (Phase V) that can operate without messing with the MAC address. (This if you're running straight Phase V without compatibility with DECnet IV routing.)

DECnet Phase IV and DECnet-Plus with Phase IV routing and some other packages can all also be set to use the DECnet MAC address for compatibility with DECnet Phase IV networking. This includes LAT and quite possibly some other pieces, and very likely also the Multinet and related DECnet pieces given that that is trying to operate with DECnet Phase IV.
Verne Britton
Regular Advisor

Re: Modified MAC address still seen after DECNET removed

well, somehow my attachment failed, trying again
Zeni B. Schleter
Regular Advisor

Re: Modified MAC address still seen after DECNET removed

Not just idle curiosity. Port security. Default setting only allows for one address. Not insurmountable but I thought switching to Decnet-over-ip would eliminate it. Decnet was Phase V but it was with Decnet IV compatibility.

Hoff
Honored Contributor

Re: Modified MAC address still seen after DECNET removed

Do you have DECnet Phase IV installed and starting, as would be typical with the Multinet DECnet over IP stuff?

Switch stuff that looks at the port is going to see multiple MAC addresses with OpenVMS, and potentially a MAC address port change for some of the operations that can be configured on OpenVMS.

You have two choices. Get rid of DECnet Phase IV entirely, either with a full migration to Phase V, or by wholesale removal of all things DECnet. Or you can remove the port restrictions at the switch.
Zeni B. Schleter
Regular Advisor

Re: Modified MAC address still seen after DECNET removed

The Switch noted by Verne Britton will likely be the solution. I will try it on the test system.

For this test system. DECNET was removed with the PRODUCT REMOVE command and I got rid of any references in the startup and I got rid of the SYS$Net_Services . The problem that I had back in June was that I needed to reboot after starting Decnet Over IP. Since I never really used the DECNET-Phase-V , I just left it off.
Steve Reece_3
Trusted Contributor

Re: Modified MAC address still seen after DECNET removed

Even if you're only using DECnet over IP, you'll still need DECnet-Plus on the box. If you don't have DECnet-Plus installed you'll need to look at other protocols such as TCP/IP and LAT.
Zeni B. Schleter
Regular Advisor

Re: Modified MAC address still seen after DECNET removed

I was remiss in my original post. I did omit that the host has Process software's Multinet package and that was the configuration that I was trying to test DECNet-over-IP .
Hoff
Honored Contributor

Re: Modified MAC address still seen after DECNET removed

Process Software has a software shim that allows DECnet Phase IV to operate over an IP network; an effective and simple alternative to the DECnet-Plus / DECnet/OSI / DECnet Phase V transition that is part of the HP DECnet-over-IP solution.