NFS Services Administrator's Guide (B.11.31.04) March 2009

Table 2-4 NFS Session Versus WebNFS Session
How WebNFS works across WANsHow NFS works across LANs
NFS servers register on port 2049. WebNFS clients
contact the WebNFS server on port 2049.
NFS servers must register their port assignments
with the portmapper service that is registered on
port 111, although the NFS server uses 2049 as
the destination port.
A WebNFS client can use the PUBLIC file handle as
an initial file handle, rather than using the MOUNT
protocol.
The MOUNT service is not registered on a specific
port. The NFS client must use the portmapper
service to locate the MOUNT port. Once the port
is located, the client must issue a request for a file
handle corresponding to the requested path.
Figure 2-2 shows a sample WebNFS session.
Figure 2-2 WebNFS Session
Figure 2-2 depicts the following steps:
1. An NFS client uses a LOOKUP request with a PUBLIC file handle to access the
foo/index.html file. The NFS client bypasses the portmapper service and
contacts the server on port 2049 (the default port).
2. The NFS server responds with the file handle for the foo/index.html file.
3. The NFS client sends a READ request to the server.
4. The NFS server responds with the data.
Removing the additional overhead of the PORTMAP and MOUNT protocols reduces
the binding time between the client and the server. The WebNFS protocol reduces the
number of over-the-wire requests and makes traversing firewalls easier.
WebNFS offers no support for locking files across mounted filesystems. Hence, multiple
clients cannot synchronize their locking calls across WebNFS mounted filesystems.
To access the shared directory across a firewall using the WebNFS feature, configure
the firewall to allow connections to the port number used by the nfsd daemon. By
default the nfsd daemon uses port 2049.
Configure the firewall based on the port number configured.
Configuring and Administering an NFS Server 43