How to set up SNMP monitoring (snmpd) on Ubuntu 12.04

  This one caused a bit of hassle recently – a few online guides don’t seem to work with the current version of Ubuntu. We found that this works, at least in the ~10 or so servers we have tried so far:  
sudo apt-get install snmpd
  Back up your snmpd.conf file:  
sudo mv /etc/snmp/snmpd.conf /etc/snmp/snmpd.conf.old
  Create a new file:  
sudo touch /etc/snmp/snmpd.conf
  Edit with your chosen editor and put in the following:  
rocommunity public syslocation “Describe the server’s location” syscontact [email protected]
  Save and exit. Now edit the following file:  
/etc/default/snmpd
  Comment out the following line by putting a # before it:  
SNMPDOPTS=’-Lsd -Lf /dev/null -u snmp -g snmp -I -smux -p /var/run/snmpd.pid’
  On the next blank line add the following:  
SNMPDOPTS=’-Lsd -Lf /dev/null -u snmp -I -smux -p /var/run/snmpd.pid -c /etc/snmp/snmpd.conf’
  Save the file and restart the SNMP daemon:  
sudo /etc/init.d/snmpd restart
  Now you should be able to successfully snmpwalk locally and from machines on the local network.