Date: Sat, 3 Mar 2001 11:15:45 -0800 (PST) From: Larry Berland <stuyman@confusion.net> To: Ted Mittelstaedt <tedm@toybox.placo.com> Cc: John Baldwin <jhb@FreeBSD.ORG>, Doug Young <dougy@gargoyle.apana.org.au>, freebsd-questions@FreeBSD.ORG Subject: RE: Promiscuous Mode ?? Message-ID: <Pine.NEB.3.96.1010303105937.29820B-100000@euphoria.confusion.net> In-Reply-To: <002901c0a2f1$cdb23440$1401a8c0@tedm.placo.com>
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On Fri, 2 Mar 2001, Ted Mittelstaedt wrote: > >[mailto:owner-freebsd-questions@FreeBSD.ORG]On Behalf Of John Baldwin > >On 01-Mar-01 Doug Young wrote: > >> Would someone please comment on the following. The machine is > >> running fine so I don't believe its anything particularly bad, but I > >> don't recall seeing that particular message previously. > > > >Do you use DHCP? Every time you get or renew a lease dhclient puts the > >interface in promiscuous mode. > > No, it doesen't - DHCP is just another service, it requests via broadcast > packets and listens for a unicast packet response on a specified port. > Correct me if I'm wrong, but when you request a lease after you've first come up (aka no IP) you put out in broadcast, and then the dhcp server will reply to you via broadcast as well. However, since the client doesn't necessarily know the broadcast (as they don't know their address or the network address) they'd be using 255.255.255.255 or 0.0.0.0 until they did, which would mean the dhcp server is binding to those addresses, instead of just its normal IP and the broadcast IP for the network. Or maybe i'm just insane. Basically, the point of this insane rant (I've been awake far too long) is that the dhcp reply initially must be broadcast, since the client has no clue what to listen to otherwise. But since the client doesn't even know the broadcast address, does that mean it gets its reply on 0.0.0.0 or 255.255.255.255, or does it just go promisc to get the reply on the normal broadcast address? Lacking in sleep, Laurence Berland http://www.isp.northwestern.edu/~laurence PS Did the chapter from TFCNG in DN get cut off? > > Ted Mittelstaedt tedm@toybox.placo.com > Author of: The FreeBSD Corporate Networker's Guide > Book website: http://www.freebsd-corp-net-guide.com > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-questions" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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