Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!samsung!uunet!sdl!gregt
From: gregt@sdl.monet.scs.com (gregt)
Newsgroups: comp.unix.wizards
Subject: Re: What is my Ethernet address?
Message-ID: <GREGT.90Aug3160420@sdl.monet.scs.com>
Date: 3 Aug 90 20:04:20 GMT
References: <432@minya.UUCP> <545@siswat.UUCP>
Sender: gregt@sdl.scs.com
Organization: Silicon Compiler Systems, Warren NJ
Lines: 53
In-reply-to: buck@siswat.UUCP's message of 2 Aug 90 06:12:50 GMT

In article <545@siswat.UUCP> buck@siswat.UUCP (A. Lester Buck) writes:

   In article <432@minya.UUCP>, jc@minya.UUCP (John Chambers) writes:
   > The only correct answer is one that gives the Ethernet address that is
   > on the card at this very instant, not one that "should" be there according
   > to some file or server which should (but may not) be correct.  I'm trying 
   > to determine whether those files and servers are correct; I can't very well 
   > ask them whether they're lying to me.  (Well, maybe I can; what does the
   > request packet look like? :-)

...

   register.  I am not really familiar with the Sun, but I thought I read at
   one time that Suns could load whatever Ethernet address they wanted from
   /etc/ethers onto the adapter.  

...

I not sure about that, but the way you read the address is by opening
/dev/nit, and hitting it with a SIOCGIFADDR ioctl - ala

	int f;
	struct ifreq if;
        if ((f = open("/dev/nit", 0)) < 0) {
                perror("open()");
                exit(1);
        }
        bzero(&if, sizeof(struct ifreq));  
        if.ifr_addr.sa_family = AF_NIT;
        strcpy(if.ifr_name, "ie0"); /* insert interface name here */     
        if (ioctl(f, NIOCBIND, &if) < 0) {
                perror("ioctl()");
                exit(2);
	}
	if (ioctl(f, SIOCGIFADDR, &if) < 0) {
                perror("ioctl()");
                exit(3);
        }
	
The address is filled in if.ifr_addr.sa_data

cheers,
greg tusar
(gregt@sdl.scs.com)


   -- 
   A. Lester Buck     buck@siswat.lonestar.org  ...!texbell!moray!siswat!buck

--
"Of all kinds of painting, figure painting is the most difficult;
then comes landscape painting, and next dogs and horses." - Ku K'ai-Chih :
gregt@sdl.scs.com // Gregory Tusar // Silicon Compiler Sys. // Warren, NJ