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Mike, > We're running the MADIS ldm distribution farm behind a load balancer. > There was a failure mode a couple of weeks ago where one of the servers > became unavailable due to software failure, but the load balancer > didn't detect it. Did the LDM fail or did something else? > It occurred to me that since we always have lots of > ldm connections, if the load balancer could detect ldm failure it > could take the server out of the farm. As far as I know, the LDM rarely, if ever, fails. > I asked our network administrator > about this and he had the following question: > > "The load balancer software supports a binary health check which I > believe LDM is a binary protocol? The LDM uses ONC RPC to communicate, which is a binary protocol. > I would just need some data to send > and/or expected data returned... in hex." > > Could he emulate ldmping to do this? If so, can you provide the actual > ldmping command and return reply? Hex would be preferable, but I can > translate from whatever form it's in. I've never looked at the messages that the RPC layers exchange when establishing a connection, so I don't know what information you would need. I have used telnet(1) to connect to an LDM port (388). telnet(1) doesn't exchange anything during the connection setup other than the normal 3-way TCP handshake. It should suffice, therefore, to simply establish a TCP connection to port 388 to determine if an LDM is running on the remote host or not. > Thanks, > > Mike Regards, Steve Emmerson Ticket Details =================== Ticket ID: XGM-432924 Department: Support LDM Priority: Normal Status: Closed