getting input/output error from NFS client on RHEL5

Question

i have two RHEL5 boxes on a private network together (192.168.2.0/24) and I am trying to export a file system from one to the other but I keep getting the following error:

mount.nfs: Input/output error

on the client side I see this output:

mount: trying 192.168.2.101 prog 100003 vers 3 prot tcp port 2049 mount: trying 192.168.2.101 prog 100005 vers 3 prot tcp port 960

and on the server side I see this:

Sep 20 14:14:32 omicron mountd[18739]: authenticated mount request from 192.168.2.87:635 for /srv/nfs/web (/srv/nfs/web)

but that's all. I opened up iptables so that the whole 192.168.2.0/24 network is allowed to communicate freely but the public side is locked down to 22,80 etc....

any ideas?

Answer 1

I had a similar problem, please have a look at this link.
And this one.

Basically you have to open much more ports.

Answer 2

Check the following:

• On the server, can you read/write to and from /srv/nfs/web?
• What's in your /etc/exports?
• What's in /etc/hosts.*
• What's in your /etc/sysconfig/iptables?
• What happens if you service iptables stop on both hosts and then try to mount it?
• The directory where you're trying to mount it you have read/write access to?
• What mount options are you using/what is the line in /etc/fstab for the mount?
• What is the output from 'showmount -a' and 'showmount -e'?

Answer 3

Make sure portmapper is running

On centos

chkconfig --list | grep portmap

To start it on centos and set it to start at boot

service portmap start chkconfig portmap on