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how to reconfig the hardware address

lovexeagle
Occasional Advisor

how to reconfig the hardware address

I am a newbie,when I use backup/image backup one Openvms 7.2.1 system to another mathine,

I use such command check
>>tcpip
tcpip>ifconfig -a
it get the same Hwaddr as the mathine before like aa:00:04:00:01:04
what my question is what this AA:00:04:00:01:04 mean? it does not like the mac addr that I see in console .
and How can I reconfig the hwaddr .
thanks for any suggest。
24 REPLIES
Karl Rohwedder
Honored Contributor

Re: how to reconfig the hardware address

The DECnet protocol changes the hardware address to AA-00-04... to reflect the DECnet address and uses this for routing purposes.
Since you 'cloned' the system, you have the same DECnet address and hence the same hardware address. To change it, give the system a new DECnet address. And remember to also change the system parameter SCSNODE and SCSSYSTEMID.
The VMS FAQ contains a section about changing a nodes's nodename (http://h71000.www7.hp.com/faq/vmsfaq_contents_001.html#toc_chapter_5).

regards Kalle
Wim Van den Wyngaert
Honored Contributor

Re: how to reconfig the hardware address

When decnet is started (is the first network protolcol to be started), the decnet address is coded into an AA address and this replaces the address of your network card.

So, unless you don't start decnet, you have an AA address.

Wim
Wim
lovexeagle
Occasional Advisor

Re: how to reconfig the hardware address

can you tell me what the decnet hwaddr means? can I just use the "clone" HWaddr aa:00:04:00:01:04 in my new mathine?


Wim Van den Wyngaert
Honored Contributor

Re: how to reconfig the hardware address

Yes. The decnet address is unique (or better should be) on your network. You can move it to any VMS machine.

Wim
Wim
lovexeagle
Occasional Advisor

Re: how to reconfig the hardware address

I find some topic to say how to change the DECnet ADDRESS and ip address
It looks like hard to me :(.

is the DECnet Address associate to the MAC address?
because I use the "clone" system to communicate to another through the Hwaddr
It seems not work.

thanks to read my awful english :)
Wim Van den Wyngaert
Honored Contributor

Re: how to reconfig the hardware address

This is a more accurate link than that of Karl.
http://h71000.www7.hp.com/wizard/wiz_4244.html

Wim
Wim
lovexeagle
Occasional Advisor

Re: how to reconfig the hardware address

thanks, but I don't understand " DECnet node 19.22 (hexadecimal 4C16)" mean, what is 19.22? and if 22d = 0x16, how get 4c?
Wim Van den Wyngaert
Honored Contributor

Re: how to reconfig the hardware address

The decnet address is in the form area.nodenumber and is mapped to a name, just like in IP.

Wim
Wim
lovexeagle
Occasional Advisor

Re: how to reconfig the hardware address

thanks for your kind helpï¼ but I still can not get the way to resolve my problemã

it seams like I should learn the openvms hardly.:(.
Wim Van den Wyngaert
Honored Contributor

Re: how to reconfig the hardware address

I'll retry.

Your network card had address A.

Decnet starts and calculates a new address B based upon the decnet address. From then on, all network protocols that start will use that address B.

If you assign the decnet address to another node and stop the old node, the address with which the new node will communicate is the same as that of the old node (that is B).

Study hard !

Wim
Wim
lovexeagle
Occasional Advisor

Re: how to reconfig the hardware address

what I want to know is why my "clone" system can not communicate to the old network through decnet Address ?

Does I must reconfig the DECnet Address?

if not, what the problem can make the network crash.

thanks for your patient answerï¼ you are a good guy :)
Wim Van den Wyngaert
Honored Contributor

Re: how to reconfig the hardware address

Not sure what you mean with "clone".

if you have 2 nodes on the same network with the same decnet config, you are in shit. 2 nodes will fight for the network packages. Result will be very messy (didn't try it yet). You will have to rename 1 of the 2 nodes or put 1 out of order (power off).

Wim
Wim
lovexeagle
Occasional Advisor

Re: how to reconfig the hardware address

the word "clone" is from karl :).
I mean "backup/image" from A to mathine B
what I want to do is B does the same function as Aã B is a backup system of Aã
they will not appear in the same network at the same timeã


Karl Rohwedder
Honored Contributor

Re: how to reconfig the hardware address

If system B is only connected to the network, if system A is down, you may leave all addresses unchanged, so that B may work as A in case of problems.

I attached a (quite crude) DCL procedure, which converts DECnet addresses to their AA... equivalent and vice versa for your information.


regards Kalle
Wim Van den Wyngaert
Honored Contributor

Re: how to reconfig the hardware address

Then read this one.
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=1038607

If the hardware is the identical the machine should work without change (licenses ?). Otherwise you might encounter some problems.

Wim
Wim
Jan van den Ende
Honored Contributor

Re: how to reconfig the hardware address

lovexeagle,

To begin with:
WELCOME to the VMS forum!

What is not yet clear to me:
Is the _ORIGINAL_ node (from which you made the system disk Backup) running at the moment?

If so, than you would be trying to get two same MAC-addresses in your network, which will not work, and therefore, you MUST reconfigure DECnet to a unique address (let's say, you chose x.y) Be sure to change SYSGEN parameter SCSSYSTEMID to (1024 * x) + y. You will then need a reboot.
After that, you get a new AA:00:.. MAC address (it is calculated automaticly).
Now you have a network, and you can configure IP.

Note: this ONLY applies when the original node of that system disk is still running, and on the same network. If not, forget about this post.

Hope this helps.

Success.

Proost.

Have one on me.

jpe
Don't rust yours pelled jacker to fine doll missed aches.
William Brown_2
Occasional Advisor

Re: how to reconfig the hardware address

You also need to check the id of the network card in the old vs the new system. If they are the same ethernet cards and the same number of cards, then it should be the same. If different you need to check...could be EIA or EWA depending on the cards.

On a running system (with phase IV Decnet)
go into NCP and give the command SHOW KNOWN CIRCUITS. This will show the known devices and their states (-ON should mean working, -off not working, -starting probably means trying but having a problem.) Also, NCP command SHOW KNOW LINES will show know lines of which some might not be know to DECnet.

You might even need to run NETCONFIG.COM to get DECnet configured with the correct config for the 'new' system if different than the old (so that DECnet has seen all the lines AND circuits).

Just some more of the many possibilities depending on the situation.

Good day,

Bill
Colin Butcher
Esteemed Contributor

Re: how to reconfig the hardware address

Hello,

OpenVMS systems can run many network protocols, not just TCP/IP. Typically you will find the following protocols in use with ethernet network interfaces:

- SCS (a layer 2 protocol used for cluster traffic)
- LAT (a layer 2 protocol used for terminal and printer traffic, usually with terminal servers, otherwise known as DECservers)
- MOP (a layer 2 protocol used for down-line loading devices, often DECservers and cluster satellites)
- DECnet (a layer 3 protocol used for node to node communication)
- TCP/IP (a layer 3 protocol used for node to node communication)

These different protocols all work in different ways and can all co-exist on the same network interfaces.

The ethernet specifications require each network interface to have a unique address - known as the MAC address (Media Access Control). The MAC address is usually based on a unique number contained in ROM on the network interface and is known as the hardware MAC address.

The interface operates with the physical MAC address, which is usually loaded from the hardware MAC address, but it can be set by the network layer drivers to an alternate value. DECnet Phase IV (and Phase V in Phase IV compatible mode) sets the physical MAC address to a known value based on the DECnet Phase IV node address.

DECnet node addresses have the format . and are node addresses - this is different to TCP/IP addressing where TCP/IP addresses are per interface.

The AA-00-04-00-xx-yy address is simply a DECnet Phase IV physical MAC address and it was loaded into the network adapter when DECnet started. Other protocols (which should be started after DECnet) then use the AA-00-04-00-xx-yy address as the MAC address, so for example a TCP/IP ARP would resolve to the AA-00-04-00-xx-yy physical MAC address, not the underlying hardware MAC address.

If you want to understand this well you need to understand ethernet addressing and the operation of the individual protocols. Here is a useful reference: http://www.ethermanage.com/ethernet/ethernet.html

You will find the conventions for address allocation in RFC1700, for example here: http://www.faqs.org/rfcs/rfc1700.html.

You may also find this technical description of DECnet Phase V (and Phase IV) useful:
http://h71000.www7.hp.com/openvms/journal/v5/index.html#decnet

To "change the address" of the second system then you will need to:
- change the DECnet Phase IV address (assuming that you are using Phase IV or Phase V in Phase IV compatible mode)
- change the TCP/IP address (or addresses if there are multiple interfaces)
- change the system name (SCSNODE and SCSSYSTEMID) via MODPARAMS.DAT and AUTOGEN
- change occurrences of the system name in command files etc.
- and so on.

See the VMS FAQ and Wizard articles for further information.

If you still need help to do this work then I'd recommend that you consider bringing in someone to help you and to teach you in the process. VMS is probably the most reliable and best operating system in existence - and it is easy to work with once you understand the basic principles. Also remember that the on-line HELP is excellent, as is the extremely comprehensive manual set. Please read them carefully.

Have fun.
Colin.
Entia non sunt multiplicanda praeter necessitatem (Occam's razor).
Chinraj Rajasekaran
Frequent Advisor

Re: how to reconfig the hardware address

Hi,

there is a useful list in the VMS FAQ
Section 5.7
http://h71000.www7.hp.com/faq/vmsfaq_007.html#mgmt9

Cheers
Raj
Steve-Thompson
Regular Advisor

Re: how to reconfig the hardware address

NiHowMa

Your initial question refers to the use of TCPIP, and most answers refer to DECnet.
Quite rightly, too.
A MAC address in the form AA-00-04-01-04 means DECnet has been started up.
(What does it mean? Transpose the 01-04 to 0401. It's a HEX number convert 401 to decimal and you get 1025. This means you have a DECnet address of 1.1! Calculated by 1.0*1024 + 1.
I hope that answers your original question.

Don't bother to try and "change it" it gets calulated by DECnet software.
DECnet software gets it from the SCSSYSTEMID sysgen parameter, which should be equal to 1025.

You CANT use systems A and B on the net at the SAME time if they both have a backup copy of the same disk, but they should work perfectly one at a time.

Are they the same system? If not, then this is where the next problem might be.

Alphas of different type configure their Line/circuit/ethernet information with a different name. the result is DECnet or TCPIP wont work because it needs reconfiguring.

DECnet is really easy to configure if this is your case.

Login as SYSTEM and look for a file called either netconfig.com or net$configure.com...

To help ....
1.
with this command you would see your TCPIP interface configuration ...
$ tcpip sho interface
and the output looks something like this:-
----------------
Packets
Interface IP_Addr Network mask Receive Send MTU

IE0 10.32.3.124 255.255.255.0 576215 244775 1500
IE1 10.32.3.125 255.255.255.0 289981 35540 1500
LO0 127.0.0.1 255.0.0.0 0 0 4096
---------------------------


2.
with this command you would see some DECnet information...
$mc ncp sho exec
and the output will be similar to this
-----------
ode Volatile Summary as of 23-AUG-2006 16:34:33

Executor node = 1.111 (MOON)

State = on
Identification = DECnet-OSI for OpenVMS
-------------

lovexeagle
Occasional Advisor

Re: how to reconfig the hardware address

thanks you all I'am so grateful for all your help!

I have backup my system successfullyã

Saju a r s
Advisor

Re: how to reconfig the hardware address

Hi ...i have a similar problem in my DS15 cluster . When i do a ifconfig -a i get the same HW address for ee0 and ee2 .
qts201:/> ifconfig -a -v
ee0: flags=c63
HWaddr aa:00:04:00:e8:1c
inet 1.1.2.232 netmask ffffff00 broadcast 1.1.2.255 ipmtu 1500

ee2: flags=c63
HWaddr aa:00:04:00:e8:1c
inet 1.1.1.232 netmask ffffff00 broadcast 1.1.1.255 ipmtu 1500

Both the interfaces are on different card.Both of them have been configured to use DECNET .But why same HW address ?
Hoff
Honored Contributor

Re: how to reconfig the hardware address

Why the same hardware address?

Because DECnet Phase IV uses the same hardware address, as has been discussed earlier in this thread. That's just the way that DECnet Phase IV addressing and Phase IV routing works.

You can connect onto the same LAN segment only if you have DECnet-Plus, also known as DECnet Phase V. This because having more than one station with the same address on the same LAN segment is forbidden.

You cannot change this behavior.

You can only choose to not start DECnet Phase IV on the secondary controllers on the same LAN segment, or you can choose to use DECnet-Plus. Or you can chunk up the LAN segment by locating DECnet routers between the segments.

Some background reading material:

http://en.wikipedia.org/wiki/DECnet

Some history: DECnet-Plus is about twenty years old now, though (for various reasons) the adoption of Phase IV and the OSI stack was and is slow; the OSI network stack was thought to be the next-generation networking stack, and IP was the next-generation networking stack. Subsequent to its product release, DECnet-Plus was upgraded and can now operate over IP, so you can use Phase IV routing and OSI routing and IP routing.

But in any case: what you are seeing is simply the way that DECnet Phase IV works.

Saju a r s
Advisor

Re: how to reconfig the hardware address

Thanks...
now i got it..