Archive for the ‘Networking’ Category
CentOS NFS How-to Guide: Exporting and Mounting a NFS Drive
This guide shows you how to start an NFS service on one (host) machine, export the NFS drive, and then connect to that NFS drive from a client machine.
## On the NFS host machine:
#Start Portmap service if needed.
#NFS uses portmap and a bunch of ports (that you can set in /etc/sysconfig/nfs) if you want.
See this link for more details on NFS ports.
#Start portmap service
service portmap status
service portmap start (if needed)
#Start NFS
service nfs start
#Edit /etc/exports
#Reference: https://www.redhat.com/docs/manuals/enterprise/RHEL-3-Manual/ref-guide/s1-nfs-server-export.html
Format is (select the options you want):
[Directory to export] [Hosts to allow](options)
/home/just_testing 192.168.0.0/24(rw,async,wdelay,root_squash)
#Run exportfs to refresh NFS exports
exportfs -av
Be sure the proper ports are open on iptables
Reference: http://pario.no/2008/01/15/allow-nfs-through-iptables-on-a-redhat-system/
## Now on your NFS client machine:
Start portmap
service portmap start
Create a mount point and mount the NFS drive. Remember to use your own server’s IP address:
mkdir /mnt/nfs-usbdisk
mount 192.168.0.2:/home/just_testing /mnt/nfs-usbdisk
Voila ! Tail your logs if you have any problems !
Resolve a hostname from an IP address in Ruby (Reverse-DNS)
It sounds easy, but I tried a lot of things before finding the solution I used.
I tried using:
`host 66.249.67.49` or
`nslookup 66.249.67.49`
These were fine, but it seems a bit hacky to use the shell. Also, it would require some sort of parsing to get the hostname that I want.
Browsing the web, I found a couple solutions that almost worked.
s = Socket.getaddrinfo('66.249.67.49',nil)
hostname = s[0][2]
This solution worked in IRB, worked in console, but for some reason would not work when I was running my mongrel server and trying to perform the exact same method call from a web-browser. ( I still don’t know why).
Digging around a bit more, I came up with this simple solution:
host = Resolv.new.getname('66.249.67.49')
Is it really that easy?? Give it a shot and let me know your thoughts !!
