thissen@pttrnl.nl (06/27/91)
Hello, Sunday the 23d of June we renumbered all our IP-addresses on our network, because we have now an class B internet address. We use subnet mask 255.255.252.0. For (subnet)routing we use the cisco AGS+. We have a problem with clients and yellow pages servers which are not on the same subnet. When PC-NFS is started on the PC, the server doesn't answer and no connection is made. The PC-NFS guide says: "If both yellow pages and reverse ARP (RARP) are used, the Yellow Pages server used during the netstart RDR process MUST be on the same subnet as the PC". We tried to solve this problem with the configuring of a helper address in the cisco-router, so UDP broadcasts are forwarded. It didn't work. The AGS+ has been connected on ethernet with one ethernet interface. We use secundary addresses for subnetting. Between the ethernet segments we use bridges. Does anyone have experience with Yellow Pages servers and clients which are not on the same subnet ? Or is it really necesary to put both client and server on the same subnet ? Thanks in advance, Laurens Thissen PTTresearch dr. Neher Labaratory The Netherlands email:LJM_Thissen@pttrnl.nl tel :(xx)31703325064
woods@ncar.ucar.edu (Greg Woods) (06/28/91)
In article <1991Jun27.104339.65104@pttrnl.nl> thissen@pttrnl.nl writes: >We tried to solve this problem with the configuring of a helper address >in the cisco-router, so UDP broadcasts are forwarded. It didn't work. The problem is that the helper-address command only forwards a specific set of UDP port numbers by default, which does not, unfortunately, include the sunrpc (portmapper) port. The only solution is to explicitly list the UDP port numbers to forward to the helper address, using the "ip forward-protocol" command. We have something like this: ip forward-protocol udp 67 ip forward-protocol udp 68 ip forward-protocol udp 69 ip forward-protocol udp 42 ip forward-protocol udp 53 ip forward-protocol udp 37 ip forward-protocol udp 137 ip forward-protocol udp 138 ip forward-protocol udp 49 ip forward-protocol udp 111 It is port 111 (sunrpc) that is missing from the default list of port numbers for helper addresses, and YP/NIS broadcasts need this port. --Greg
ercm20@castle.ed.ac.uk (Sam Wilson) (06/28/91)
thissen@pttrnl.nl writes: > We have a problem with clients and yellow pages servers which are not > on the same subnet. I can't argue with Greg's analysis, but we found another way around the problem, namely to put a YP slave server on the same subnet as the clients. The slave can download its maps from the master and the clients' UDPs can then get to the slave directly. We aren't doing this currently - we moved the whole YP/NIS domain into the same subnet - and we had some problems which may or may not have been related, but it might be worth trying. Sam Wilson Network Services, Edinburgh University Computing Service, Scotland, UK