When you run NFS server it will pick random ports for mountd and nlockmgr which can change upon reboot causing nightmares when the nfs is going through a firewall.
You can lock these ports down so that its not random anymore
edit /etc/sysconfig/nfs and put in the following
STATD_PORT=4001
LOCKD_TCPPORT=4002
LOCKD_UDPPORT=4002
MOUNTD_PORT=4003
and restart the nfs services
now if you look at the port assignments via rpcinfo you will see that mountd and nlockmgr is locked into a specific port
# rpcinfo -p
program vers proto port
100000 2 tcp 111 portmapper
100000 2 udp 111 portmapper
100003 2 udp 2049 nfs
100003 3 udp 2049 nfs
100003 4 udp 2049 nfs
100003 2 tcp 2049 nfs
100003 3 tcp 2049 nfs
100003 4 tcp 2049 nfs
100021 1 udp 4001 nlockmgr
100021 3 udp 4001 nlockmgr
100021 4 udp 4001 nlockmgr
100021 1 tcp 4002 nlockmgr
100021 3 tcp 4002 nlockmgr
100021 4 tcp 4002 nlockmgr
100005 1 udp 4003 mountd
100005 1 tcp 4003 mountd
100005 2 udp 4003 mountd
100005 2 tcp 4003 mountd
100005 3 udp 4003 mountd
100005 3 tcp 4003 mountd
