Difference between ifconfig down and ifdown
 

What is the difference in the following:
"ifconfig down lo" and "ifdown lo"?
Can anyone please explain the internal behavoial differenced?

ifdown will wrap ifconfig with the network configuration files, e.g. /etc/sysconfig/network-scripts/ifcfg-eth0 on redhat based systems. Bringing down the interface is fairly simple, but the differences are much more apparent if you comapre ifup with ifconfig

Do you mean to say that the ifdown will run low level utilities such as ifconfig and route to do the job? Since it is just a wrapper, then the internal fucntionality remain same?

Could you also explain the scenario when ifup is used instead of ifconfig up?

yes, ifdown will execute "ifconfig down" inside it.

if you run "ifup eth0" it will fetch the config file and bring up the interface with the correct IP address, mask, routes etc. "ifconfig eth0 up" would just start the interface with no IP etc.

OK .. Thanks for the response :)