It isn't a name resolution problem. It works with hostname or ip-address if I mount without access. I suspect the problem is the different syntax for exporting. But don't know how I can fix it.
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Thanks trying solution.
Yes, I do exportfs –afor exporting and take both ways sam and manually.
I tried your options
mount -o vers=2,proto=udp bach:/tausch /mnt/mnt_bach2
but I get the...