Unix/Linux
Contents
DNS not working
Ping to an IP address works
ping 74.125.136.103
but this doesn't
ping www.google.com
Check resolv.conf
cat /etc/resolv.conf nameserver 95.130.132.17 nameserver 95.130.132.18
I had changed internet provider and forgot to update this. Just to set it to the router address and let that do the resolution
nameserver 192.168.1.1
Setup Oracle Enterprise Linux (RedHat) with yum server
You need to download the yum .repo file from the server, as per the steps below. After this, you need to enable a flag in the .repo file as per your operating system version. Having done these two steps, when you run yum install <pkgname> command on your linux box, the Oracle's yum server will be scanned, the dependent & the relevant rpm's will be download and installed for you.
cd /etc/yum.repos.d
To download files here
wget http://public-yum.oracle.com/public-yum-el5.repo
A file named public-yum-el5.repo will be created in your directory Edit this file and enter enabled=1 against the operating systems which is relevant to you
vi public-yum-el5.repo
Next run the yum command
yum install package-name
To change to static IP address
As root:
cd /etc/networks vi interfaces
replace the line “iface eth0 inet dhcp” with
iface eth0 inet static address 192.168.1.100 netmask 255.255.255.0 gateway 192.168.1.1
You should also take a look at the file /etc/resolv.conf and check it has a nameserver entry (probably pointing at your default gateway) or direct to your ISP name servers.
nameserver 192.168.1.1
Run a command on lots of servers in parallel
This is a damn fine AIX utility - part of the CSM Distributed Shell.
dsh -a "ls -al /etc/apache2/*conf"
will list the Apache configuration file on all reachable servers (nodes)
