Change the software source from CDROM to Internet in Debian 6

nano /etc/apt/sources.list


comment out the CDROM portion such as




#deb cdrom:[Debian GNU/Linux 6.0.0 _Squeeze_ - Official i386 DVD Binary-1 20110$


#deb cdrom:[Debian GNU/Linux 6.0.0 _Squeeze_ - Official i386 DVD Binary-1 20110$


Put these lines below


deb http://security.debian.org/ squeeze/updates main contrib
deb-src http://security.debian.org/ squeeze/updates main contrib non-free