Friday, September 17, 2010

Setting up an NFS server for CentOS

These steps show how to setup a basic NFS server for CentOS.

For the NFS Server side:

1. Make sure you've installed NFS server by typing on the terminal:

  • rpm -qa | grep nfs
This will show:
  • chkconfig --level 35 nfs on
  • service nfs start

2. Go to System>Administration>Server Settings> NFS

3. Click Add:

  • in my example, I chose /var/ftp as the directory which I will share for the network and * for hosts (this will accept all client, best practice is enter the specific ipaddr and netmask e.g. for testing purposes only.
  • On User Access tab choose Treat remote root user as local root.
4. After that, this will show...

note: I also added some directories.

5. Now, on the tricky part...

NFS has a dynamic port assigned by the portmap... (so what does that mean?) You'll have difficulty filtering those port on the firewall.

So to do that ->

  • gedit /etc/sysconfig/nfs
  • uncomment or remove the # sign on these port configuration
  • Then save.
6. Restart the services

  • service nfs restart
  • service portmap restart
note: check if the port was used by typing "rpcinfo -p"

7. We're nearly done, now on to the firewall. Type on to the terminal "gedit /etc/sysconfig/iptables" and add these to filter those port that we just enabled.

-A RH-Firewall-1-INPUT -s -m state --state NEW -p udp --dport 111 -j ACCEPT
-A RH-Firewall-1-INPUT -s -m state --state NEW -p tcp --dport 111 -j ACCEPT
-A RH-Firewall-1-INPUT -s -m state --state NEW -p tcp --dport 2049 -j ACCEPT
-A RH-Firewall-1-INPUT -s -m state --state NEW -p tcp --dport 32803 -j ACCEPT
-A RH-Firewall-1-INPUT -s -m state --state NEW -p udp --dport 32769 -j ACCEPT
-A RH-Firewall-1-INPUT -s -m state --state NEW -p tcp --dport 892 -j ACCEPT
-A RH-Firewall-1-INPUT -s -m state --state NEW -p udp --dport 892 -j ACCEPT
-A RH-Firewall-1-INPUT -s -m state --state NEW -p tcp --dport 875 -j ACCEPT
-A RH-Firewall-1-INPUT -s -m state --state NEW -p udp --dport 875 -j ACCEPT
-A RH-Firewall-1-INPUT -s -m state --state NEW -p tcp --dport 662 -j ACCEPT
-A RH-Firewall-1-INPUT -s -m state --state NEW -p udp --dport 662 -j ACCEPT
  • First, change the ipaddr and netmask specified to your Server IP address. In my example I used as my Server IP address.
  • Second, add these lines before the...
-A RH-Firewall-1-INPUT -j REJECT --reject-with icmp-host-prohibited
  • Save and restart iptables services by typing "service iptables restart"
8. We're done. Disabling the firewall will be much lesser work because you don't have to do Step 5 up to the firewall settings.

Now on to the Client Side:

1. There's no daemon to start nfs client. Just make a directory on to the /mnt by typing "mkdir /mnt/nfs" (on this example I use nfs, you can enter whatever name here).

2. Then mounting the folder...

  • type "mount -t nfs /mnt/nfs"
  • This will mount the shared folder by the server.
3. For troubleshooting,

  • make sure that you can see the portmap on the server by "rpcinfo -p" (or the IP address of your server).
  • Repeat Step 5.
  • make sure that there's no typo.
  • disable the firewall.
4. Done.

Please let me know if you have any questions or any non-violent inputs :). Cheers!

Friday, September 3, 2010

Installing alsa-driver in CentOS

First, I can assure you that linux is effin not driver friendly especially in Enterprise versions such as RHEL and CentOS. So let's get things started.

1. Make sure you have the SBx00 Azalia (Intel HDA) by typing at the terminal -> 'lspci | grep Audio' (case sensitive w/o the quote).

Having this audio device esp. in laptops, have high possibility that your experiencing no audio on the speaker, mic is not working or headphone jack doesn't work either. Editing the /etc/modprobe.conf and adding to the option line "model='whatever model alsa said on its website doesn't work either'".

If you manage to have a workaround on this without doing the next step. Please let me know.

2.If you tried mixing up the settings in 'alsamixer' and still no luck, go fire up the terminal and 'cd' to '/etc/yum.repos.d'.

3. Type 'touch ATrpms.repo'. Then 'gedit ATrpms.repo' for easier editing.

4. Copy and paste this to the file and save.

name=EL $releasever - $basearch - ATrpms

5. Copy paste to terminal:

rpm --import

6. 'yum install alsa-driver'

7. This will install 2 additional packages, the kml and the kernel update. After install, reboot.

8. You may also want to include the 'kernel-devel' and 'kernel-headers' just incase you will rebuild any device conflicts on the kernel update. (e.g. my fglrx driver for ATI)

9. After reboot, you can notice now that there's a headphone volume and addtl mic volume.