tkevans@fallst.UUCP (Tim Evans) (01/05/91)
I'm adding 4 VAX 11/750's with *binary-only* 4.2BSD licenses
(previously running on an XNS network) to a TCP/IP
network. The network is a Class B network, with a 255.255.255.0
netmask. 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.
What can be done with 4.2BSD to make things work?
PLEASE NOTE: As indicated above, we do not have source for
4.2BSD. (Long story, not appropriate here.)
Thank you.
--
UUCP: {rutgers|ames|uunet}!mimsy!woodb!fallst!tkevans
INTERNET: tkevans%fallst@wb3ffv.ampr.org
Tim Evans 2201 Brookhaven Ct, Fallston, MD 21047bob@MorningStar.Com (Bob Sutterfield) (01/06/91)
In article <1873@fallst.UUCP> tkevans@fallst.UUCP (Tim Evans) writes:
What can be done with 4.2BSD to make [subnets] work?
Euthanasia? :-)
Proxy ARP can fool old IP implementations into dealing with modern
networks. Get tut.cis.ohio-state.edu:pub/proxyarp/proxyarpd.shar.Z
and run it on something nearby that already knows about subnetting.root@bvsatl.UUCP (Super user) (01/08/91)
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. > > What can be done with 4.2BSD to make things work? > > PLEASE NOTE: As indicated above, we do not have source for > 4.2BSD. (Long story, not appropriate here.) 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 than the B42 hosts. In other words, configure your router to reply with its ethernet address whenever it sees an arp request on a subnetwork that it does not belong on. This way, the older hosts will think that the whole network lives on the one ethernet cable and the routers will take care of the rest. Obviously a better solution is to upgrade the hosts, but we all know how that goes (8-)). Bill VerSteeg -- Bill VerSteeg internet bvs@nrc.com UUCP gatech.edu!galbp!bagend!bvsatl!bvs
rickert@mp.cs.niu.edu (Neil Rickert) (01/08/91)
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 <rickert@cs.niu.edu> Northern Illinois Univ. DeKalb, IL 60115 +1-815-753-6940