Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!decvax!decwrl!pyramid!hplabs!ucbvax!oddjob.UUCP!matt From: matt@oddjob.UUCP.UUCP Newsgroups: mod.protocols.tcp-ip Subject: Re: more interesting features of 4.2 Message-ID: <8606102247.AA07738@oddjob> Date: Tue, 10-Jun-86 18:47:30 EDT Article-I.D.: oddjob.8606102247.AA07738 Posted: Tue Jun 10 18:47:30 1986 Date-Received: Wed, 11-Jun-86 18:58:31 EDT References: <12211785351.33.HEDRICK@RED.RUTGERS.EDU> Sender: daemon@ucbvax.BERKELEY.EDU Reply-To: "Matt Crawford" Organization: The ARPA Internet Lines: 30 Approved: tcp-ip@sri-nic.arpa It turns out that you can specify routing entries that will cause a host to treat destinations on that network as local. I.e. it will issue ARP's for them, just as if they were on the local Ethernet. The correct form is route add 0 if you want to set this up as a default. I tried "route add usan-net oddjob 0" some time ago, trying to access the USAN satellite net through our VitaLink box. This works to NCAR (where all hosts' addresses are on usan-net) if they do the corresponding operation on their end. The trouble comes when you want to specify that a host on the other net is a gateway to yet another net. The route-adding code insists that you can't do it. I then wrote a pseudo-interface driver which claims an interface address of "oddjob" (192.5.73.2) but a broadcast address of "usan-net" (192.17.4.0). This works OK (I'm still using it), but still has some drawbacks. One is that the other end (U of I at Urbana in this case) would have to put up a similar pseudo- interface on their gateway to usan-net before their networks and our networks are fully connected. Another is that broadcasts such as RIP packets sent to usan-net generate ICMP messages from other hosts on the local net here. I don't think any arrangement will really work satisfactorily if it has bridges connecting nets with different IP numbers. Matt Crawford