WebNFS had a fixed TCP/UDP port number (2049), and instead of requiring the client to contact the MOUNT RPC service to determine the initial filehandle of every filesystem, it introduced the concept of a public filehandle (null for NFSv2, zero-length for NFSv3) which could be used as the starting point. WebNFS was an extension to NFSv2 and NFSv3 allowing it to function behind restrictive firewalls without the complexity of Portmap and MOUNT protocols. Using TCP as a transport made using NFS over a WAN more feasible, and allowed the use of larger read and write transfer sizes beyond the 8 KB limit imposed by User Datagram Protocol. While several vendors had already added support for NFS Version 2 with TCP as a transport, Sun Microsystems added support for TCP as a transport for NFS at the same time it added support for Version 3. At the time of introduction of Version 3, vendor support for TCP as a transport-layer protocol began increasing. This became an acute pain point for Digital Equipment Corporation with the introduction of a 64-bit version of Ultrix to support their newly released 64-bit RISC processor, the Alpha 21064.
By July 1992, implementation practice had solved many shortcomings of NFS Version 2, leaving only lack of large file support (64-bit file sizes and offsets) a pressing issue. The principal motivation was an attempt to mitigate the performance issue of the synchronous write operation in NFS Version 2. The first NFS Version 3 proposal within Sun Microsystems was created not long after the release of NFS Version 2. a READDIRPLUS operation, to get file handles and attributes along with file names when scanning a directory.additional file attributes in many replies, to avoid the need to re-fetch them.support for asynchronous writes on the server, to improve write performance.support for 64-bit file sizes and offsets, to handle files larger than 2 gigabytes (GB).NFSv2 only allows the first 2 GB of a file to be read due to 32-bit limitations. By February 1986, implementations were demonstrated for operating systems such as System V release 2, DOS, and VAX/VMS using Eunice. The Virtual File System interface allows a modular implementation, reflected in a simple protocol.
People involved in the creation of NFS version 2 include Russel Sandberg, Bob Lyon, Bill Joy, Steve Kleiman, and others. Its designers meant to keep the server side stateless, with locking (for example) implemented outside of the core protocol. Version 2 of the protocol (defined in RFC 1094, March 1989) originally operated only over User Datagram Protocol (UDP).
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