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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!news.mira.net.au!news.netspace.net.au!news.mel.connect.com.au!news.syd.connect.com.au!news.bri.connect.com.au!fjholden.OntheNet.com.au!news From: Tony Griffiths <tonyg@OntheNet.com.au> Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: Two devices with same IP Date: Tue, 26 Nov 1996 12:07:37 +1000 Organization: On the Net (ISP on the Gold Coast, Australia) Lines: 47 Message-ID: <329A50E9.3EE6@OntheNet.com.au> 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> Reply-To: tonyg@OntheNet.com.au NNTP-Posting-Host: swanee.nt.com.au Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 3.0 (WinNT; I) To: kbigelow@www.play-hookey.com 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. > Ken > > Are you interested in | > byte-sized education | http://www.play-hookey.com > over the Internet? | Tony