PTR record needed to mount NFS share
I was trying to mount an NFS share form an ESXi host, but it failed with an "unable to connect to nfs server" error all the time, with no more details than that. I ended up doing a tcpdump capture on the FreeNAS unit to find out that it was doing a PTR DNS query and it failed because I didn't have a DNS server available in that network. Once I allowed it to communicate with a DNS server from another network, the share would mount. Once the datastore created in ESXi, the DNS server is not necessary anymore.
Is that a bug or a feature?