I have a Ubuntu-server. I am trying to install Vsftpd but it shows the : Reading package lists... Done Building dependency tree Reading state information... Done E: Couldn't find package vsftpd After that I checked internet connection by ping 4.2.2.4 and there was no problem in internet connection. I tried to apt-get update but it was not possible it shows: Err http://us.archive.ubuntu.com lucid Release.gpg Temporary failure resolving 'us.archive.ubuntu.com'