apt-cache polic:

100 /var/lib/dpkg/status
     release a=now
 500 http://security.debian.org etch/updates/non-free Packages
     release o=Debian,a=stable,l=Debian-Security,c=non-free
     origin security.debian.org
 500 http://security.debian.org etch/updates/contrib Packages
     release o=Debian,a=stable,l=Debian-Security,c=contrib
     origin security.debian.org
 500 http://security.debian.org etch/updates/main Packages
     release o=Debian,a=stable,l=Debian-Security,c=main
     origin security.debian.org
 500 http://ftp.nl.debian.org etch/main Packages
     release v=4.0r1,o=Debian,a=stable,l=Debian,c=main
     origin ftp.nl.debian.org
 500 cdrom://[Debian GNU/Linux 4.0 r0 _Etch_ - Official i386 CD Binary-1 20070407-11:55] etch/main Packages
     origin Debian GNU/Linux 4.0 r0 _Etch_ - Official i386 CD Binary-1 20070407-11:55
 500 cdrom://[Debian GNU/Linux 4.0 r0 _Etch_ - Official i386 CD Binary-1 20070407-11:55] etch/contrib Packages
     origin Debian GNU/Linux 4.0 r0 _Etch_ - Official i386 CD Binary-1 20070407-11:55

sources.list:

#
# deb cdrom:[Debian GNU/Linux 4.0 r0 _Etch_ - Official i386 CD Binary-1 20070407-11:55]/ etch contrib main

deb cdrom:[Debian GNU/Linux 4.0 r0 _Etch_ - Official i386 CD Binary-1 20070407-11:55]/ etch contrib main

deb http://ftp.nl.debian.org/debian/ etch main
deb-src http://ftp.nl.debian.org/debian/ etch main

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