Date: Fri, 20 Mar 1998 08:56:56 -0600 (CST) From: "Matthew D. Fuller" <fullermd@futuresouth.com> To: GLEN.W.MANN@monsanto.com Cc: freebsd-questions@FreeBSD.ORG Subject: Re: Re[2]: arp/IP to ethernet addresses Message-ID: <Pine.BSF.3.96.980320084444.20071a-100000@shell.futuresouth.com> In-Reply-To: <"0320144044-Re2: arp/IP to ethernet addresses"@MHS>
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On 20 Mar 1998 GLEN.W.MANN@monsanto.com wrote: > > (Pardon my cc:Mail!) > > The purpose is asset control verification. Basically an on-demand thing. > If ifconfig -a gives > > lp0: flags=8810<POINTOPOINT,SIMPLEX,MULTICAST> mtu 1500 > ep0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 > inet 123.456.6.80 netmask 0xfffffe00 broadcast 123.456.7.255 > inet 123.456.6.81 netmask 0xffffffff broadcast 123.456.6.81 > ether 00:a0:24:25:e4:59 > tun0: flags=8010<POINTOPOINT,MULTICAST> mtu 1500 > sl0: flags=c010<POINTOPOINT,LINK2,MULTICAST> mtu 552 > ppp0: flags=8010<POINTOPOINT,MULTICAST> mtu 1500 > lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384 > inet 127.0.0.1 netmask 0xff000000 > > then I use 123.456.7.255 as broadcast? This will cross a (rather slow) > WAN link (modem bank or something) to subnet 123.456.7. If I ping > 123.456.6.255 will I be restricted to the local subnet (123.456.6)? Well, if the interfaces are setup to see 123.456.7.255 as the broadcast address, they won't say a darn thing back if they get 123.456.6.255. I'm not sure how that would work, with the subnet divided over multiple local networks; with parts of it on different sides of a router, I'm not sure how the broadcast address will get routed. However, you won't get arp entries for systems on the other side of the router; you'd have to have a system on each (physical) network to catalog the MAC addresses. > The ping manpage talks about pinging a multicast address. Is this the same > thing? No, that's an experimental technology, having to do with referencing a given set of hosts with a single address. It might, theoretically, solve your problem, but implementing it would be a lot of trouble. But I'm not too knowledgeable about multicasting; I'll let someone else handle that one. It MIGHT be a solution, but probably a whole lot more work that it's worth. *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* | FreeBSD; the way computers were meant to be | * "The only reason I'm burning my candle at both ends, is * | that I haven't figured out how to light the middle yet."| * fullermd@futuresouth.com :-} MAtthew Fuller * | http://keystone.westminster.edu/~fullermd | *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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