Thomas Plant via CentOS wrote:

Hello all,

I have an NFS Server where I want give access to a specific address to a specific path. Problem is that I have some other shares active which I do not want the specific IP to not access it.

The /etc/exports looks like the following:

/nfs/Share1             10.10.*(rw) /nfs/Share2             10.10.*(rw) /kdnbckp/CS21           10.10.193.43(rw)

The client on the last line (IP 10.10.193.43) I'd like to exclude from mounting the first two shares.

How can I do this? 'man exports' does not give any hint if this is possible.

I don't know of an option to exclude a single host - but you might be able to do something clever with the 'refer' option ...

BTW, the export man page says that you shouldn't use wildcards in IP network addresses - i.e. instead of exporting to '10.10.*', you should use '10.10.0.0/16'

So something like the following may work:

/nfs/Share1 10.10.193.43(rw,refer=/dummy@127.0.0.1) 10.10.0.0/16(rw) /nfs/Share2 10.10.193.43(rw,refer=/dummy@127.0.0.1) 10.10.0.0/16(rw) /kdnbckp/CS21 10.10.193.43(rw)

The above _should_ cause the client at 10.10.193.43 to attempt to mount "/dummy" from itself when it tries to mount either /nfs/Share1 or /nfs/Share2 from the server - and if "/dummy" isn't exported from itself (or if NFS isn't running), then the mount will fail ...

However, I believe the refer= option is NFSv4 only - so if the client attempts an NFSv3 mount, it will successfully mount from the server (and not use the refer mount point) - i.e. to make sure this doesn't happen, you will need to disable NFSv3 (and NFSv2) access - e.g see:

https://opsech.io/posts/2016/Jan/26/nfsv4-only-on-centos-72.html

However, the above is all a bit messy - so I would be interested if you come across a simpler way of achieving this ...

James Pearson