Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!maverick.ksu.ksu.edu!ux1.cso.uiuc.edu!mp.cs.niu.edu!rickert From: rickert@mp.cs.niu.edu (Neil Rickert) Newsgroups: comp.unix.questions Subject: Re: Getting 4.2BSD to Understand Subnetted Network Message-ID: <1991Jan8.005247.216@mp.cs.niu.edu> Date: 8 Jan 91 00:52:47 GMT References: <1873@fallst.UUCP> <183@bvsatl.UUCP> Organization: Northern Illinois University Lines: 28 In article <183@bvsatl.UUCP> root@bvsatl.UUCP (Super user) writes: >In article <1873@fallst.UUCP>, tkevans@fallst.UUCP (Tim Evans) writes: >> 4.2BSD seems not to understand subnetting, so the >> first such machine on the net sees only itself and a few >> others (386's with an older TCP/IP) which also don't understand >> subnetting. >> >Assuming that you are using a decent router to connect your subnets, >it should be able to proxy arp for the hosts on a different subnet The original complaint is not completely clear. If there is a problem with any TCP communications, then proxy arp should handle it. But the complaint may have been the inability to see 'rwhod' messages, etc. In this case there is not much you can do about it. The problem then is not the subnet mask, but the broadcast address. Since the 4.3 broadcast address specifies all '1' bits for the host section, whereas 4.2 broadcasts use all '0' bits. So solving the subnet problem is not a complete answer. If broadcasts are real important, you can probably configure the 4.3 hosts to use the 4.2 broadcasts and subnetting. But that will prevent them seeing 4.3 broadcasts (such as routing packets), so the cure may be worse than the disease. -- =*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*= Neil W. Rickert, Computer Science Northern Illinois Univ. DeKalb, IL 60115 +1-815-753-6940