When at the console prompt on your VAX client, entering the following commands will output the ethernet address for the on board ethernet adapter.
A.1 Obtaining The Ethernet Address of Your MicroVAX 2000 or VAXstation 2000.
>>> test 50
This will print out quite a few lines of information. The line starting with "ID" is the one that references the VAX's ethernet address.
ID 08-00-2B-16-59-BB
A.2 Obtaining The Ethernet Address of Your MicroVAX 3100, VAXstation 3100, or VAXserver 3100.
>>> show ether
ID 08-00-2B-16-59-BB