From owner-freebsd-questions Fri Mar 20 06:41:39 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id GAA04610 for freebsd-questions-outgoing; Fri, 20 Mar 1998 06:41:39 -0800 (PST) (envelope-from owner-freebsd-questions@FreeBSD.ORG) Received: from gatekeeper3.monsanto.com (gatekeeper3.monsanto.com [199.89.234.123]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id GAA04600 for ; Fri, 20 Mar 1998 06:41:35 -0800 (PST) (envelope-from GLEN.W.MANN@monsanto.com) From: GLEN.W.MANN@monsanto.com Received: by gatekeeper3.monsanto.com; id IAA28866; Fri, 20 Mar 1998 08:41:35 -0600 Received: from nplxsl01.monsanto.com(164.144.252.39) by gatekeeper3.monsanto.com via smap (3.2) id xma028393; Fri, 20 Mar 98 08:41:10 -0600 Received: by nplxsl01.monsanto.com (NPlex 2.0.082); 20 Mar 1998 08:41:09 -0600 To: fullermd@futuresouth.com, freebsd-questions@FreeBSD.ORG Subject: Re[2]: arp/IP to ethernet addresses Message-Id: <"0320144044-Re2: arp/IP to ethernet addresses"@MHS> Date: 20 Mar 1998 09:29:20 -0600 MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG (Pardon my cc:Mail!) The purpose is asset control verification. Basically an on-demand thing. If ifconfig -a gives lp0: flags=8810 mtu 1500 ep0: flags=8843 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 mtu 1500 sl0: flags=c010 mtu 552 ppp0: flags=8010 mtu 1500 lo0: flags=8049 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)? The ping manpage talks about pinging a multicast address. Is this the same thing? Thanks again... -Glen Mann ______________________________ Reply Separator Subject: Re: arp/IP to ethernet addresses Author: fullermd@futuresouth.com at INTERNET Date: 3/19/98 4:19 PM On 19 Mar 1998 GLEN.W.MANN@monsanto.com wrote: > Hello! > > On the network at work, we would like the ability to match ethernet > addresses (e.g., 00:a0:24:12:34:56) to IP addresses. Dynamically? Or once-over? For what purpose, if I may ask? > The output for `arp -a' is confusing. It shows more IP addresses than > there are hosts in our DNS namedb tables, but not a full listing of > all the machines on the network. What other than explicit action, > updates the arp tables? Some time ago, `arp -a' showed me many more > entries, perhaps all the machines on the network. Is there a way to > cause the translation tables to be more complete? I'm not sure exactly what you're saying here. The arp tables should hold every MAC address that the host has talked to (fairly recently) on the local network, with no routers in between. If they haven't talked, there's no MAC address stored. > If I build a script to send pings (one per) to each possible IP > address on the net, the arp table is built. Is this a good idea? Might be better to ping the broadcast address once. Unless is breaks your network with the load, I can't imagine it's necessarily a *bad* idea. Doesn't mean it's *good*, but... > The man pages say the arp stuff works with 10Mbit ethernet, though it > seems to work with 100Mbit as well. I guess the man pages are > outdated? Never thought of it that way. I always thought of arp as a function of Ethernet, regardless of speed. *shrug* *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* | 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