Otdfbt

I'm troubleshooting an NFS issue, and found something unexpected: rpcinfo reports different output depending on what client I run it from. What would cause this? (inherited server; no idea if it was purposely configured this way, or how)

This is the (correct, expected) output I get on a random machine that does not need to mount the NFS share:

me@random_client:~$ rpcinfo -p nfs_server.example.com
 program vers proto port service
 100000 4 tcp 111 portmapper
 100000 3 tcp 111 portmapper
 100000 2 tcp 111 portmapper
 100000 4 udp 111 portmapper
 100000 3 udp 111 portmapper
 100000 2 udp 111 portmapper
 100024 1 udp 35726 status
 100024 1 tcp 55115 status
 100003 2 tcp 2049 nfs
 100003 3 tcp 2049 nfs
 100003 4 tcp 2049 nfs
 100227 2 tcp 2049
 100227 3 tcp 2049
 100003 2 udp 2049 nfs
 100003 3 udp 2049 nfs
 100003 4 udp 2049 nfs
 100227 2 udp 2049
 100227 3 udp 2049
 100021 1 udp 46086 nlockmgr
 100021 3 udp 46086 nlockmgr
 100021 4 udp 46086 nlockmgr
 100021 1 tcp 47752 nlockmgr
 100021 3 tcp 47752 nlockmgr
 100021 4 tcp 47752 nlockmgr
 100005 1 udp 36001 mountd
 100005 1 tcp 36810 mountd
 100005 2 udp 44952 mountd
 100005 2 tcp 37364 mountd
 100005 3 udp 42206 mountd
 100005 3 tcp 49171 mountd

This is the (incorrect, unexpected) output I get on the machine that does need to mount the NFS share.

me@desired_client:~$ rpcinfo -p nfs_server.example.com
 program vers proto port service
 100000 4 tcp 111 portmapper
 100000 3 tcp 111 portmapper
 100000 2 tcp 111 portmapper
 100000 4 udp 111 portmapper
 100000 3 udp 111 portmapper
 100000 2 udp 111 portmapper
 100024 1 udp 52768 status
 100024 1 tcp 60092 status
 100021 1 udp 35877 nlockmgr
 100021 3 udp 35877 nlockmgr
 100021 4 udp 35877 nlockmgr
 100021 1 tcp 39358 nlockmgr
 100021 3 tcp 39358 nlockmgr
 100021 4 tcp 39358 nlockmgr

What gives? Why am I not seeing NFS?

Update: showmount results

correct, expected output from random machine that does not need to mount the NFS share:

me@random_client:~$ showmount -e nfs_server.example.com
Export list for nfs_server.example.com:
/mnt/sharedrive desired_client,otherclient1,otherclient2

incorrect, unexpected output from the machine that does need to mount the NFS share:

me@desired_client:~$ showmount -e nfs_server.example.com
clnt_create: RPC: Program not registered

Google suggests that RPC: Program not registered indicates the NFS server isn't running, but clearly that's not happening here since the other machine can see it just fine?

Ahahahahahaha, this was an own goal.

me@desired_client:~$ cat /etc/hosts
127.0.0.1 localhost
127.0.0.1 nfs_server.example.com
[...]

The offending loopback entry was apparently added by IT after desired_client went bonkers a few weeks ago when nfs_server went down for repairs unexpectedly. They didn't mention they'd fixed it by modifying hosts...

(sometimes brute force works -- i figured it out by going through /etc in reverse chronological order)