Troubleshooting of NFS service port problems

NFS settings are complex. Especially in the firewall and port problems, we need to pay more attention. Today, we will explain how to set ports for the NFS service. First, let's take a look at the problem in the workshop, and then find a solution.

Problem description

When debugging the MMS interface machine LINUX, You need to mount a directory on the AIX server to the MMS interface machine. There is a firewall between the MMS interface machine and the AIX server. In this case, you need to open the firewall port. Since each time AIX restarts the NFS service, the mountd port will change and you need to specify the port.

Solution

First, check which ports are occupied when the NFS service is started on AIX and perform the following operations:

 
 

  
  
#rpcinfo -p  
  
  
program vers proto port service  
  
  
100000 4 udp 111 portmapper  
  
  
100000 3 udp 111 portmapper  
  
  
100000 2 udp 111 portmapper  
  
  
100000 4 tcp 111 portmapper  
  
  
100000 3 tcp 111 portmapper  
  
  
100000 2 tcp 111 portmapper  
  
  
100083 1 tcp 32769 ttdbserver  
  
  
100068 2 udp 32769 cmsd  
  
  
100068 3 udp 32769 cmsd  
  
  
100068 4 udp 32769 cmsd  
  
  
100068 5 udp 32769 cmsd  
  
  
200012 2 udp 970  
  
  
200012 3 udp 971  
  
  
100003 2 udp 2049 nfs  
  
  
100003 3 udp 2049 nfs  
  
  
100003 2 tcp 2049 nfs  
  
  
100003 3 tcp 2049 nfs  
  
  
100003 4 tcp 2049 nfs  
  
  
200006 1 udp 2049  
  
  
200006 4 udp 2049  
  
  
200006 1 tcp 2049  
  
  
200006 4 tcp 2049  
  
  
100005 1 tcp 32783 mountd  
  
  
100005 2 tcp 32783 mountd  
  
  
100005 3 tcp 32783 mountd  
  
  
100005 1 udp 32786 mountd  
  
  
100005 2 udp 32786 mountd  
  
  
100005 3 udp 32786 mountd  
  
  
400005 1 udp 32787  
  
  
100024 1 tcp 32784 status  
  
  
100024 1 udp 32788 status  
  
  
100133 1 tcp 32784  
  
  
100133 1 udp 32788  
  
  
200001 1 tcp 32784  
  
  
200001 1 udp 32788  
  
  
200001 2 tcp 32784  
  
  
200001 2 udp 32788  
  
  
100021 1 udp 32813 nlockmgr  
  
  
100021 2 udp 32813 nlockmgr  
  
  
100021 3 udp 32813 nlockmgr  
  
  
100021 4 udp 32813 nlockmgr  
  
  
100021 1 tcp 32785 nlockmgr  
  
  
100021 2 tcp 32785 nlockmgr  
  
  
100021 3 tcp 32785 nlockmgr  
  
  
100021 4 tcp 32785 nlockmgr 
 
 

From the above, we can see that the ports 111 and 2049 used by the NFS service are fixed, but mountd often changes. You can specify mountd as a fixed port, so that after NFS is started every time, all the ports used are fixed ports.

Operation Method:

Run the following command on the NFS server:

 
 

  
  
# Cp/etc/services. bak
  
  
# Find the following line in vi/etc/services:
  
  
#1001-1009 # Unassigned
 
 

Before this line, enter mountd 1001/tcp mountd 1001/udp

 
 

  
  
# Rmnfs-N stop the NFS service
  
  
# Nfso-po nfs_use_reserved_ports = 1
  
  
# Mknfs-N start the NFS service
 
 

In this way, port 1001 is fixed as the NFS mountd port.

Then open TCP and UDP ports 111, 2049, and 1001 on the firewall. The NFS output directory on the AIX server can be mounted successfully by testing the mount on the MMS interface machine.