in /etc/firewalld/zone/mycustomzone.xml I use the syntax of <port protocol="tcp" port="2049"/> to open port number being a protocol choice of either tcp or udp. For NFSv4 only port 2049 needs to be opened, so when NFS proto=tcp then open firewall port protocol tcp. And when NFS proto=udp then firewalld protocol=udp.

Are there other valid choices besides tcp and udp there for firewalld?

Using RHEL 8.7 with NFS v4.2 working, when doing mount it reports my mounts typically having proto=tcp. But when I have RDMA working it says proto=rdma.

I know RDMA happens over port 20049 (by default). What is the relationship of RDMA to TCP/UDP, and do I just need to do both

<port protocol="tcp" port="2049"/>
<port protocol="udp" port="2049"/>

in my firewalld xml file where both protocols need to be allowed for RDMA? Or should only one of those two be opened and if so which one? I don't think firewalld supports protocol=rdma does it?


  • the original title to this post was NFS proto=rdma and firewalld tcp/udp protocol relationship
  • with only firewalld port=22 tcp open and firewalld running on both the nfs-server and nfs-client computers, a mount server:/data /data will fail (because port 2049 tcp is not open) but a mount -o rdma server:/data /data is successful
    • on the client the rdma mount shows server:/data on /data type nfs4 (rw,relatime,vers=4.2,rsize=1048576,wsize=1048576,namlen=255,hard,proto=rdma,port=20049,timeo=600,retrans=2,sec=sys,clientaddr=,local_lock=none,addr=
    • this is in RHEL 8.7
    • my observation seems to prove nfs via rdma is not affected by firewalld. is this to be expected given how rdma is supposed to be direct access ?

1 Answer 1


RDMA is technology to by-passing the kernel , and iptables is a module of the linux kernel , so firewalld will not work for any RDMA connections.

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