Post by thread:[OT] Network Card Address

It depends a fair bit on the OS as to whether you can do this. You generally cannot pre-specify the MAC address on a card; the entire point of the MAC address system is to have guaranteed-unique device IDs. (MAC being "media access control", and the MAC address consisting of a three-byte OUI -- organizationally unique identifier -- followed by the three-byte device ID; the OUI is that of the card manufacturer, and is assigned by the IEEE.) However, the MAC address is stored in ROM on the card and read in by the driver in the operating system, which generally will then uses the in-memory copy of the address in formatting and receiving packets. Depending on the sophistication of the driver and the utilities made available by the OS, you may be able to override the MAC address on the card; the OS driver will then just use the MAC address you tell it to instead of the one on the card. In most UNIX systems, this is implemented as an option on the ifconfig command. This won't make your two systems look identical from a hardware standpoint, but if you always override the MAC address on both machines, then you will be able to make them functionally identical from a whole-system perspective. This probably won't help you if you need to net-boot those machines, unless you have some fancy cards (I don't know of any that will do this) that will let you override the MAC address in firmware. You may be able to do this on a Sun in the Open Boot Prom, but you weren't talking about Suns. --Bob On Tue, Mar 30, 1999 at 09:55:03AM -0500, Montaigne, Mike wrote: > I need two network cards with the same address, > Does anyone where I can buy two/another card > with a specified address? > > I want to set up two PC's to look exactly the same. > > tks > > Mike -- ============================================================ Bob Drzyzgula It's not a problem .....bobKILLspam@spam@drzyzgula.org until something bad happens ============================================================

Hmmm. Are you using MediaOne for Internet access? Alan -----Original Message----- From: Montaigne, Mike <.....montaignemKILLspam.....AECL.CA> To: EraseMEPICLISTspam_OUTTakeThisOuTMITVMA.MIT.EDU <PICLISTspam_OUTMITVMA.MIT.EDU> Date: Tuesday, March 30, 1999 10:05 AM Subject: Re: [OT] Network Card Address {Quote hidden}>I need two network cards with the same address, >Does anyone where I can buy two/another card >with a specified address? > >I want to set up two PC's to look exactly the same. > >tks > >Mike >

Cabletron E21xx and E22xx cards allow you to manually set the MAC address using supplied software. -----Original Message----- From: Montaigne, Mike <@spam@montaignemKILLspamAECL.CA> To: <KILLspamPICLISTKILLspamMITVMA.MIT.EDU> Date: Tuesday, March 30, 1999 9:57 AM Subject: Re: [OT] Network Card Address {Quote hidden}>I need two network cards with the same address, >Does anyone where I can buy two/another card >with a specified address? > >I want to set up two PC's to look exactly the same. > >tks > >Mike >

Some earlier cards use a (GAL? small ROM or PROM? I forget what part it is! Been a while.) - little 16-pin DIL chip to store the MAC address. Get two of those, copy one of the GALs (eeProms? Whatever the heck they are!), and you're set, worst case. I can probably find you two of such cards, you'll know you have such a card as it usually has a SOCKET in there with a DIL plugged in that has a 6-hex-digit ID number (the second half of the MAC address), actually I have some Gateway Communications Ethernet cards (10Base T/2 combo cards, jumpered type) that should have one, I can go find one & see what part they have plugged in. If you can deal with 2 of those (Ne2000 clone), I can sure sell them off (I've since moved to SMC cards.) Though SMC's may do it all in NVRam, and be configurable. Think cards like a 3C501, for the type of card I'm thinking of here. You'll see a little paper label (hand-written or machine-printed) with 6 Hex digits on it, atop a DIL-16 chip. Think lowish performance, too, compared to 100BaseT <G> Which may be just fine, for what you want! Mark Montaigne, Mike wrote: {Quote hidden}> > I need two network cards with the same address, > Does anyone where I can buy two/another card > with a specified address? > > I want to set up two PC's to look exactly the same. > > tks > > Mike

The MAC address can be overridden. It's called locally administired address. It's a parameter on the command line or a field in the driver screen. Depending on which OS/protocal you are working with. Can't think why you might want to do it. Oh well, have at it. >From: Mark Willis <RemoveMEmwillisTakeThisOuTNWLINK.COM> >Reply-To: pic microcontroller discussion list <spamBeGonePICLISTspamBeGoneMITVMA.MIT.EDU> >To: TakeThisOuTPICLISTEraseMEspam_OUTMITVMA.MIT.EDU >Subject: Re: [OT] Network Card Address >Date: Wed, 31 Mar 1999 11:56:19 -0800 > >Some earlier cards use a (GAL? small ROM or PROM? I forget what part >it is! Been a while.) - little 16-pin DIL chip to store the MAC >address. Get two of those, copy one of the GALs (eeProms? Whatever the {Quote hidden}>heck they are!), and you're set, worst case. I can probably find you >two of such cards, you'll know you have such a card as it usually has a >SOCKET in there with a DIL plugged in that has a 6-hex-digit ID number >(the second half of the MAC address), actually I have some Gateway >Communications Ethernet cards (10Base T/2 combo cards, jumpered type) >that should have one, I can go find one & see what part they have >plugged in. If you can deal with 2 of those (Ne2000 clone), I can sure >sell them off (I've since moved to SMC cards.) Though SMC's may do it >all in NVRam, and be configurable. > > Think cards like a 3C501, for the type of card I'm thinking of here. >You'll see a little paper label (hand-written or machine-printed) with 6 >Hex digits on it, atop a DIL-16 chip. > > Think lowish performance, too, compared to 100BaseT <G> Which may be >just fine, for what you want! > > Mark > >Montaigne, Mike wrote: >> >> I need two network cards with the same address, >> Does anyone where I can buy two/another card >> with a specified address? >> >> I want to set up two PC's to look exactly the same. >> >> tks >> >> Mike > Get Your Private, Free Email at http://www.hotmail.com