Setting Advanced Preferences

Use the Advanced tab to select the transport mechanism, the NFS version, and determine how to specify the NFS port.

Transport

Select which transport to use. Automatic tries TCP first and then UDP. Using the UDP transport speeds up network traffic by reducing packet overhead on LANs and high-speed reliable networks. TCP works better when high reliability of packet transmission is a requirement, as on WANs where transmission speed is slower and more errors are encountered. TCP is able to recover one bad packet without requiring the whole frame to be resent. TCP waits for acknowledgment that a packet arrived, and if it does not receive one, it retransmits the packet.

NFS Version

You can speed up connections to the network by specifying what version of NFS to use. If the servers to which you most often connect support only one version, configure that version as a default. Automatic tries v3 first and then tries v2.

If a server is running Solaris 2.5 or later, its default NFS version is v3, but it can use v2 if the client needs to use v2. If a server is running Solaris 2.4 or earlier, it can only run NFS v2.

For any UNIX server, including one running a brand of UNIX other than Solaris, you can find out which NFS version it supports using the rpcinfo command, as follows:

rpcinfo -p hostname | grep 100003

(NFS is RPC program #100003.)

Running this command on a Solaris 2.5 system would return the following, which means that v2 and v3 are supported over UDP and TCP.

100003     3     udp     2049     nfs  
100003     2     tcp      2049	     nfs  
100003     3     tcp      2049     nfs  
100003     2     udp     2049     nfs

Running this command on a Solaris 2.4 system would return the following, which means that only v2 is supported over UDP.

100003     2     udp     2049     nfs

Compare the output for a non-Solaris system to determine which NFS version it supports.

NFS Port

Determine how to specify a port.

• Use Portmapper tells NFS to use the Portmapper program to determine which port to use. Using Portmapper is less efficient than using a specific port, but frees you from having to know the NFS server's listening port number.

• Use A Specific Port tells NFS to use the port you specify instead of using Portmapper. Using a specific port speeds up NFS operations. The NFS specification suggests port number 2049 as the standard NFS server port. Your network may choose to use another port number.

WebNFS

Select this option if you are using WebNFS through a firewall. If this option is selected, the client will try to use the public file handle to locate files and directories on the server. If the server does not support the public file handle, the mount will fail.