NFS Client: Backup preparation problem

[Amit Karpe]

Hi All,
I am not able to access particular directory on client which is mounted
using NFS.

client# ls -l /mnt/tmp
ls: cannot access /mnt/tmp/del: Permission denied
total 0
?????????? ? ? ? ?                ? del

I have following disk on server.
server# ls -ld /disk12
drwxrwxr-- 3 root root 4096 2013-02-28 15:53 /disk12

Entry in /etc/exports on server.
/disk12   172.21.123.219(rw,sync)


On client
Entry in /etc/fstab
172.21.123.225:/disk12                  /mnt/tmp      nfs
fsc,rsize=32768,wsize=40960,rw  0 0

If I used no_root_squash in /etc/exports on server I can access directory
without problem.
/disk12   172.21.123.219(rw,sync,no_root_squash)


What can be the problem ?

[Michael E. Maher]

Hi Amit,

On Thu, 2013-02-28 at 17:39 +0800, Amit Karpe wrote:
>  
>  If I used no_root_squash in /etc/exports on server I can access
>  directory without problem.
>  /disk12   172.21.123.219(rw,sync,no_root_squash)
>  
>  What can be the problem ?
>   
You have kind of answered your own question here. If you need root
access to the files from the client, you will need the 'no_root_squash'.
All that option does is honour your clients root user over the NFS share
(not great for security but I don't know your set up details).

Other than that you'd have to manage the users on both systems, to be
the same name/uid/gid etc.. and do everything as a non-root user (better
for security).

Take a look at this link[0] and hopefully that should clear it all up.


Thanks,
Michael


[0]http://www.troubleshooters.com/linux/nfs.htm#_If_it_mounts_but_cant_access

[Amit Karpe]

On Fri, Mar 1, 2013 at 2:35 AM, Michael E. Maher
<michael(a)maheronline.co.uk&gt;wrote:

>  Hi Amit,
>
>  On Thu, 2013-02-28 at 17:39 +0800, Amit Karpe wrote:
>  >
>  > If I used no_root_squash in /etc/exports on server I can access
>  > directory without problem.
>  > /disk12   172.21.123.219(rw,sync,no_root_squash)
>  >
>  > What can be the problem ?
>  >
>
>  You have kind of answered your own question here. If you need root
>  access to the files from the client, you will need the 'no_root_squash'.
>  All that option does is honour your clients root user over the NFS share
>  (not great for security but I don't know your set up details).
>
>  Other than that you'd have to manage the users on both systems, to be
>  the same name/uid/gid etc.. and do everything as a non-root user (better
>  for security).
>
>  Take a look at this link[0] and hopefully that should clear it all up.
>
>
>  Thanks,
>  Michael
>
>
>  [0]
>  http://www.troubleshooters.com/linux/nfs.htm#_If_it_mounts_but_cant_access
>
>
>  
Michael,
In following situation if I access as root or non-root, I am facing same
"Permission denied" error.
So the problem is just not with root but all users.

client# ls -l /borneo4
ls: cannot access /borneo4/test-dir: Permission denied
?????????? ? ? ? ?                ? test-dir
client# su - eos
client$ ls -lh /borneo4/
ls: cannot access /borneo4/test-dir: Permission denied
total 0
?????????? ? ? ? ?                ? test-dir



And on server side I am ready change file permissions. By
changing ownership of directory will solve this problem without using
no_root_squash ?

-- 
Regards
Amit Karpe.
http://www.amitkarpe.com/
http://news.karpe.net.in/