kmail hangs due to missing loopback interface

My /etc/network/interfaces got deleted when I removed mepis-network package. Everything was fine, except that kmail would hang since IP address 127.0.0.1 doesn't exist. It took me half an hour to figure it out. Had to create the file with these lines in it:

auto lo  
iface lo inet loopback

Now things went back to normal.