NFS, FreeBSD-server -> Ubuntu-klient

 The pathnames must not have any symbolic
     links in them and should not have any "." or ".." components.

The third component of a line specifies the host set to which the line
     applies.  The set may be specified in three ways.  The first way is to
     list the host name(s) separated by white space.  (Standard Internet
     ``dot'' addresses may be used in place of names.)  The second way is to
     specify a ``netgroup'' as defined in the netgroup file (see netgroup(5)).
     The third way is to specify an Internet subnetwork using a network and
     network mask that is defined as the set of all hosts with addresses
     within the subnetwork.  This latter approach requires less overhead
     within the kernel and is recommended for cases where the export line
     refers to a large number of clients within an administrative subnet.

     The first two cases are specified by simply listing the name(s) separated
     by whitespace.  All names are checked to see if they are ``netgroup''
     names first and are assumed to be hostnames otherwise.  Using the full
     domain specification for a hostname can normally circumvent the problem
     of a host that has the same name as a netgroup.  The third case is speci-
     fied by the flag -network=netname and optionally -mask=netmask.  If the
     mask is not specified, it will default to the mask for that network class
     (A, B or C; see inet(4)).  See the EXAMPLES section below.

     -t      Set the initial retransmit timeout to the specified value.  May
             be useful for fine tuning UDP mounts over internetworks with high
             packet loss rates or an overloaded server.  Try increasing the
             interval if nfsstat(1) shows high retransmit rates while the file
             system is active or reducing the value if there is a low retrans-
             mit rate but long response delay observed.  (Normally, the -d
             option should be specified when using this option to manually
             tune the timeout interval.)

mount.nfs remotetarget dir [-rvVwfnsih] [-o nfsoptions]

       timeo=n        The time (in tenths of a second) the  NFS  client  waits
                      for a response before it retries an NFS request. If this
                      option is not specified, requests are retried  every  60
                      seconds  for NFS over TCP.  The NFS client does not per‐
                      form any kind of timeout backoff for NFS over TCP.

                      However, for NFS over UDP, the client uses  an  adaptive
                      algorithm  to  estimate an appropriate timeout value for
                      frequently used request types (such as  READ  and  WRITE
                      requests),  but  uses the timeo setting for infrequently
                      used request types (such as FSINFO  requests).   If  the
                      timeo option is not specified, infrequently used request
                      types  are  retried  after  1.1  seconds.   After   each
                      retransmission,  the  NFS client doubles the timeout for
                      that request, up to a maximum timeout length of 60  sec‐
                      onds.