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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!news.mel.connect.com.au!munnari.OZ.AU!spool.mu.edu!uwm.edu!cs.utexas.edu!math.ohio-state.edu!howland.erols.net!feed1.news.erols.com!news From: Ken Bigelow <kbigelow@www.play-hookey.com> Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: Two devices with same IP Date: Tue, 26 Nov 1996 19:27:43 +0000 Organization: Erol's Internet Services Lines: 56 Message-ID: <329B44AF.5CAC@www.play-hookey.com> References: <56ltqk$nhv@csugrad.cs.vt.edu> <56lvvc$62f$1@gail.ripco.com> <32920988.63E7@www.play-hookey.com> <571pde$mp8@sf18.dseg.ti.com> <3294A324.902@www.play-hookey.com> <329A50E9.3EE6@OntheNet.com.au> Reply-To: kbigelow@www.play-hookey.com NNTP-Posting-Host: kenjb05.play-hookey.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 3.0 (Win16; U) Tony Griffiths wrote: > > Ken Bigelow wrote: > > > > > > >network_interfaces="cuaa1 lnc0 lo0" > > > >ifconfig_cuaa1="inet 206.161.179.129 netmask 255.255.255.224" > > Basically this says that there is a NETWORK (206.161.179.128->.159) > accessible thru this interface, which is wrong. That network is > acutally off the Ethernet interface. It happens to work simply because > there are NO addresses other than the .129 on the cuaa0 side! A netmask > of 255.255.255.255 is more correct since this is a point-to-point > connection to another network (your ISP). > > > > >ifconfig_lnc0="inet 206.161.179.129 netmask 255.255.255.224 mtu 1006" > > > >ifconfig_lo0="inet localhost" > > > > > > > > > > >Seems to still be working fine. > > > > > > > ifconfig -a shows both interfaces present, with ppp0 happily connected > > to my ISP's port. netstat -i shows both interfaces happily coexisting, > > with different numbers of Ipkts and Opkts, as appropriate. > > > > We have been doing this for several months now. What error would you > > expect to pop up now to cause a problem, and why hasn't it done so > > already??? From observed behavior, if the system isn't bug-free, it's > > doing a darn good imitation so far! > > -- > It probably works because the P-to-P flag is set on the cuaa0 interface > and the MULTICAST flag is set on the lnc0 interface, so arping for MAC > addresses is done on the correct interface. I presume that your DEFAULT > route is pointing to the IP address on the other end of the ppp link and > that end is setup with the correct NETMASK so returning packets are > correctly routed to you. > > In fact a look at the routing tables in your ISP's router/t-server would > show a P-to-P route to .129 with netmask of all 1's and a network route > for 206.161.179.128 with netmask 255.255.255.224. > I answered Tony by e-mail before my news server showed this as a post. I will only note here that as long as my link (ppp0) to my ISP is active, I can't even access cuaa1; it is completely taken over. Since ppp0 is designated POINTTOPOINT in ifconfig -a, and I only specified 206.161.179.129 (without /27) in /etc/ppp/options, I can only assume that whatever I said for cuaa1 is overridden and ppp0 uses just the singleton address. -- Ken Are you interested in | byte-sized education | http://www.play-hookey.com over the Internet? |