diff --git a/o/OpenMPI/OpenMPI-4.0.0-GCC-6.3.0-2.27.eb b/o/OpenMPI/OpenMPI-4.0.0-GCC-6.3.0-2.27.eb
index c9539939..bd5aaccd 100644
--- a/o/OpenMPI/OpenMPI-4.0.0-GCC-6.3.0-2.27.eb
+++ b/o/OpenMPI/OpenMPI-4.0.0-GCC-6.3.0-2.27.eb
@@ -42,6 +42,11 @@ configopts += '--enable-mpi-cxx '  # Enable building the C++ MPI bindings
 # needed for --with-verbs
 osdependencies = [('libibverbs-dev', 'libibverbs-devel', 'rdma-core-devel')]
 
+postinstallcmds = [
+    'echo "# By default, for Open MPI 4.0 and later, infiniband ports on a device are not used by default." >> %(installdir)s/etc/openmpi-mca-params.conf',
+    'echo "btl_openib_allow_ib = true" >> %(installdir)s/etc/openmpi-mca-params.conf',
+]
+
 libs = ["mpi_mpifh", "mpi", "ompitrace", "open-pal", "open-rte"]
 sanity_check_paths = {
     'files': [