Setting up a user-specified port range

The /etc/services file must define the port number entries for services mountd, mvsmount, pcnfsd, showattr , network status monitor (status), and network lock manager (nlockmgr) of the z/OS NFS server. Figure 1 outlines the port numbers for these services, with contiguous port numbers 2043-2049 as examples.

Figure 1. Modify /etc/services for mountd, mvsmount, pcnfsd, showattr, status, and nlockmgr

# NFS server                                                        
#                                                                   
#  Port 2049 must be used for nfsd.                                 
#                                                                   
#  Consecutive port numbers must be assigned for the NFS status,    
#   nlockmgr, mountd, mvsmount, showattr, and pcnfsd services.      
#   The example belows uses ports 2043-2048.  
#                      
#  When the NFS callback function is being used the services        
#   nfsscb_b and nfsscb_e should reserve 100 consecutive ports.     
#   The example below uses port 10300 for the beginning port        
#   and port 10399 as the ending port.                              
#  For additional information see the Network File System Guide     
#   and Reference manual.                                           
#                                                                   
Service       port/protocol  Alias        Description  
status          2043/tcp   nfs_statd     # NFS State daemon (NSM)   
status          2043/udp   nfs_statd     # NFS State daemon (NSM)   
nlockmgr        2044/tcp   nfs_lockd     # NFS Lock daemon (NLM)    
nlockmgr        2044/udp   nfs_lockd     # NFS Lock daemon (NLM)    
mountd          2045/tcp   mount         # NFS mount daemon         
mountd          2045/udp   mount         # NFS mount daemon         
mvsmount        2046/tcp   nfs_mvsmnt    # NFS mvsmount daemon      
mvsmount        2046/udp   nfs_mvsmnt    # NFS mvsmount daemon      
showattr        2047/tcp   nfs_showattr  # NFS showattr daemon      
showattr        2047/udp   nfs_showattr  # NFS showattr daemon      
pcnfsd          2048/udp   nfs_pcnfs     # NFS pcnfsd daemon        
pcnfsd          2048/tcp   nfs_pcnfs     # NFS pcnfsd daemon        
nfsd            2049/tcp   nfs           # NFS server daemon        
                                         #  - do not change         
nfsd            2049/udp   nfs           # NFS server daemon        
                                         #  - do not change         
#                                                                   
#  NFS Callback function port range                                 
#                                                                   
nfsscb_b       10300/tcp                 # NFSS callback port begin 
nfsscb_e       10399/tcp                 # NFSS callback port end   
nfsscb_b       10300/udp                 # NFSS callback port begin 
nfsscb_e       10399/udp                 # NFSS callback port end

The user specified range of ports provides a flexible port range to accommodate programs such as a firewall that supports a range of ports for security purposes between the NFS Client and the NFS Server. Firewall security honors a limited port range so the NFS server has to allow the user to specify a few server ports in /etc/services to narrow the port ranges used for programs mountd, mvsmount, pcnfsd and showattr.

The tcpip.profile file must define the port range entries for services nfsd, mountd, mvsmount, pcnfsd, showattr, status, and nlockmgr of the z/OS NFS server. Figure 2 outlines the port ranges for these seven services with contiguous port numbers 2043-2049 as examples, starting with port 2043 for the network status monitor.

Figure 2. Modify tcpip.profile for z/OS NFS server services

PORTRANGE 2043 7 UDP mvsnfs ; Reserved for startup JCL, 
                            ;     mvsnfs                     
PORTRANGE 2043 7 TCP mvsnfs ; Reserved for startup JCL, 
                            ;     mvsnfs
PORTRANGE 10300 100 UDP mvsnfs   ; Reserved for startup JCL,
                            ;     mvsnfs
PORTRANGE 10300 100 TCP mvsnfs   ; Reserved for startup JCL,
                            ;     mvsnfs

Note: Check the z/OS USS BPXPRMxx parmlib member for INADDRANYPORT and INADDRANYCOUNT. Their range cannot include the z/OS NFS server port ranges for the server to initialize. See z/OS Communications Server: IP Configuration Guide for more details.

If the z/OS NFS server is started in the TCP/IP Autolog section, then the NOAUTOLOG parameter should be specified on the PORTRANGE statement, unless there will always be listeners/sockets on all ports defined in the statement. For additional information, refer to the section on AUTOLOG in z/OS Communications Server: IP Configuration Reference.

Add the following two lines in /etc/rpc on the client side to see mvsmount and showattr information:

mvsmount         100044   mvsmount
showattr         100059   showattr

The query result from the client side will show the following messages:

# rpcinfo -p hostname
    program   vers     proto      port    service     
    100000    2        tcp        111     portmapper  
    100000    2        udp        111     portmapper  
    100024    1        udp        2043    status
    100024    1        tcp        2043    status
    100021    1        udp        2044    nlockmgr
    100021    1        tcp        2044    nlockmgr
    100021    3        tcp        2044    nlockmgr
    100021    3        udp        2044    nlockmgr
    100021    4        tcp        2044    nlockmgr
    100021    4        udp        2044    nlockmgr
    100005    1        udp        2045    mountd      
    100005    1        tcp        2045    mountd      
    100005    3        udp        2045    mountd      
    100005    3        tcp        2045    mountd 
    100044    1        udp        2046    mvsmount    
    100044    1        tcp        2046    mvsmount  
    100059    2        udp        2047    showattr    
    100059    2        tcp        2047    showattr    
    150001    1        udp        2048    pcnfsd
    150001    2        udp        2048    pcnfsd
    150001    1        tcp        2048    pcnfsd
    150001    2        tcp        2048    pcnfsd
    100003    2        udp        2049    nfs         
    100003    2        tcp        2049    nfs         
    100003    3        udp        2049    nfs         
    100003    3        tcp        2049    nfs
    100003    4        tcp        2049    nfs