I'm trying to test the MPI publish-connect methods and running into a situation where for some reason MPI_LOOKUP_NAME is returning the wrong port. You can see the test source and output in the attached zipfile. I'm testing this (on Ubuntu 16.04, MPICH 3.2) by opening 2 terminal windows and starting one group of 2 processes (the 'server' group) in one, and another group (the 'client' group) in another. Beforehand I've started the hydra name server using hydra_nameserver & (in the same terminal session as the server group) The exact command line for the server group is: mpiexec -nameserver DeepThought -n 1 ./MPI_Example_C_0 server : -n 1 ./MPI_Example_C_1 server and for the client group: mpiexec -nameserver DeepThought -n 1 ./MPI_Example_C_0 client : -n 1 ./MPI_Example_C_1 client If you look at the attached output files, you can see that the problem is straightforward: MPI_LOOKUP_NAME is returning the wrong port name for the server group. Rather surprisingly, too, it *always* returns the exact same port name for any run: tag#0$description#DeepThought$port#50178$ifname#127.0.1.1$127.0.P even though the port name reported for the server varies: in this run it was tag#0$description#DeepThought$port#33341$ifname#127.0.1.1$ The clients are clearly performing the lookup and successfully querying the nameserver because if I don't run the server and simply run the clients they abort saying they couldn't find a published port, as expected. So something strange is going on. Has anyone run into this? Is there something I need to do otherwise? Thanks for any help. Alex Rast _______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss