Hi there On 22/08/17 18:01, Thomas Schmitt wrote: <Cut>
Question is whether it can be unambiguously recognized in netstat output as long as it is visible. Further: Is it always only one hidden port ?
It's always a callback from a Stretch NFS server to a Jessie NFS client. It occurs when the client mounts. The port moves from established, to wait to hidden.
When the Jessie box mounts a dir exported by Stretch, the Stetch box does a callback. When the Stretch box mounts a dir exported by the Jessie box, the Jessie box doesn't callback.
As a temporary fix a disabled the callback by mounting with NFS version three (vers=3) on the Jessie box.
Regards, Rob