Andrew Kershaw wrote: > I'm not entirely certain of this, but I think the MAC address for the > ethernet "card" on newer (read PCI-based) Macs is set in OpenFirmware.
Actually, the MAC address is set in silicon, as it were, in the Ethernet hardware. Apple Lan Utility (which he mentioned) allows you to override it on a number of Mac models, including the 7500, 8500 and 9600. Newer ones may be changable in Open Firmware, as you said. There are circumstances where changing the MAC address is desirable and necessary (the Readme included with ALU mentions SNA and DECNet environments. They shut down the DECNet here at the U something like 7 or 8 years ago...), though spoofing other devices is the usual reason to do so anymore. Here is the relevant section regarding DECNet: (from <http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/decnet.htm> ) " DECnet hosts do not use manufacturer-assigned Media Access Control (MAC)-layer addresses. Instead, network level addresses are embedded in the MAC-layer address according to an algorithm that multiplies the area number by 1024 and adds the node number to the product. The resulting 16-bit decimal address is converted to a hexadecimal number and is appended to the address AA00.0400 in byte-swapped order, with the least-significant byte first. For example, DECnet address 12.75 becomes 12363 (base 10), which equals 304B (base 16). After this byte-swapped address is appended to the standard DECnet MAC address prefix, the address is AA00.0400.4B30." To put anything on a DECNet network, you gotta spoof the MAC address.... And this concludes todays 'Ancient Computing History' lesson... -- Bruce Johnson University of Arizona College of Pharmacy Information Technology Group Institutions do not have opinions, merely customs -- PowerBooks is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Enter To Win A | -- Canon PowerShot Digital Cameras start at $299 | Free iBook! | Support Low End Mac <http://lowendmac.com/lists/support.html> PowerBooks list info: <http://lowendmac.com/lists/powerbooks.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/powerbooks%40mail.maclaunch.com/> --------------------------------------------------------------- >The Think Different Store http://www.ThinkDifferentStore.com ---------------------------------------------------------------
