I've been configuring an Exchange 5.5 cluster: I've now got (had) Outlook working with the Exchange 5.5 Enterprise server but I was struggling to contact our X.400 connection server to the external world and now, in an attempt to fix it have messed up the entire cluster!!!: This might sound a bit complex: (The IP addresses have been changed for security:) The Outlook Windows 95 PCs could ping: 148.252.7.4 yes 148.252.28.31 yes 148.252.28.21 yes 148.252.007.017 yes node1 and node2 could ping: 148.252.7.4 yes 148.252.28.21 no 148.252.28.31 no 148.252.007.017 yes The network setting for node 1 WERE: Default Gateway: 148.252.7.1 (which nothing in the building seems to ping!) IP Address: 148.252.7.10 Subnet mask: 255.255.252.0 Node 2 IP Address: 148.252.7.11 Cluster (virtual server) IP Address: 148.252.7.12 I changed the subnet mask on node 1 to: 255.255.0.0 rebooted and ALL the addresses were then pingable (although ...28.21 sometimes timed out amongst a batch of pings). The subnet mask on both nodes and the cluster itself were 255.255.252.0. When trying to fail the cluster over from node 2, I found that the IP address component on the cluster was unhappy, but everything else in the resource group, MTA, cluster drives, etc. were happy AND the connection to our X.400 server worked (i.e. 148.252.28.21 and 148.252.28.31 pinged) and email that had been queued in Exchange got delivered .. hoorah!! THIS IS THE IMPORTANT BIT: I then changed the subnet mask on node 1, node 2 AND the cluster to 255.255.0.0 thinking that this was a good thing and now, the cluster WILL NOT COMMUNICATE WITH CLUSTER ADMINISTRATOR!!! HELP!!!! I cannot mount any drives, I cannot do anything with it. I know this is a bit in depth, but I think my only alternative is to rebuild the cluster which I'd really, really rather not do! I've changed the masks back to 255.255.252.0 on both nodes / on one node / rebooted etc.. but the cluster refuses to talk. I thought that the new mask would make it responsive to a greater range of IP addresses, not less! How do I correct it? Any help, very, very, very, very much appreciated!! ============================================= Rajendra Varsani Pesticides Safety Directorate Ministry of Agriculture, Fisheries and Food York, England 01904 455804 ------------------ Please respond to r.varsani@psd.maff/gov/uk Any opinions expressed in this email may not necessarily reflect the opinions of The Ministry