This determines which hosts have read-only access to this share. There are three choices for this option :

- None
  No hosts have read-only access.
- All hosts
  Any host can mount this share read-only. If you are connected to the Internet, this means that anyone in the world can read files in the exported directory.
- Listed hosts
  The hosts or IP addresses listed below can mount this share read-only. Matching hosts listed below can mount this share read-only. Hosts can be specified in the following ways :

  Hostname or IP address (like ftp.foo.com or 1.2.3.4)
    Matches the host with the given name or address
  Netgroup (like engineering)
    Matches any host that is a member of the netgroup
  DNS domain (like .foo.com)
    Matches any host in the domain
  Network (like @10.254.1)
    Matches any host in the network
  Network/netmask (like @10.254.1/24)
    Matches any host in the network

  In addition, any of the above notations can be prefixed by a -, meaning that the host, netgroup, domain or network is not allowed to mount this share. This can be useful for allowing access by a set of hosts, but denying one member.