Open MPI is currently compiled without IPv6 support, which can be confirmed with # /usr/lib64/openmpi/bin/ompi_info |grep IPv6 IPv6 support: no This makes it impossible to use on IPv6-only networks, among other things. This is the RHEL 9 version of https://bugzilla.redhat.com/show_bug.cgi?id=2119845
Put up https://gitlab.com/redhat/centos-stream/rpms/openmpi/-/merge_requests/6 for this