marc@ubuntu:~$ sudo apt-get update
Err http://ubuntu.cities.uiuc.edu dapper-updates Release.gpg
  Could not resolve 'ubuntu.cities.uiuc.edu'
Err http://ubuntu.cities.uiuc.edu dapper Release.gpg
  Could not resolve 'ubuntu.cities.uiuc.edu'
Get:1 http://security.ubuntu.com dapper-security Release.gpg [189B]
Err http://ubuntu.cities.uiuc.edu dapper-backports Release.gpg
  Could not resolve 'ubuntu.cities.uiuc.edu'
Get:2 http://us.archive.ubuntu.com dapper Release.gpg [189B]
Hit http://security.ubuntu.com dapper-security Release
Ign http://ubuntu.cities.uiuc.edu dapper-updates Release
Hit http://us.archive.ubuntu.com dapper Release
Ign http://ubuntu.cities.uiuc.edu dapper Release
Hit http://security.ubuntu.com dapper-security/main Packages
Ign http://ubuntu.cities.uiuc.edu dapper-backports Release
Hit http://us.archive.ubuntu.com dapper/main Packages
Ign http://ubuntu.cities.uiuc.edu dapper-updates/main Packages
Hit http://security.ubuntu.com dapper-security/restricted Packages
Hit http://security.ubuntu.com dapper-security/main Sources
Hit http://us.archive.ubuntu.com dapper/restricted Packages
Hit http://us.archive.ubuntu.com dapper/main Sources
Ign http://ubuntu.cities.uiuc.edu dapper-updates/restricted Packages
Ign http://ubuntu.cities.uiuc.edu dapper-updates/main Sources
Hit http://security.ubuntu.com dapper-security/restricted Sources
Hit http://security.ubuntu.com dapper-security/universe Packages
Hit http://security.ubuntu.com dapper-security/universe Sources
Hit http://us.archive.ubuntu.com dapper/restricted Sources
Ign http://ubuntu.cities.uiuc.edu dapper-updates/restricted Sources
Ign http://ubuntu.cities.uiuc.edu dapper/universe Packages
Ign http://ubuntu.cities.uiuc.edu dapper/multiverse Packages
Ign http://ubuntu.cities.uiuc.edu dapper/universe Sources
Ign http://ubuntu.cities.uiuc.edu dapper/multiverse Sources
Ign http://ubuntu.cities.uiuc.edu dapper-backports/main Packages
Ign http://ubuntu.cities.uiuc.edu dapper-backports/restricted Packages
Ign http://ubuntu.cities.uiuc.edu dapper-backports/universe Packages
Ign http://ubuntu.cities.uiuc.edu dapper-backports/multiverse Packages
Ign http://ubuntu.cities.uiuc.edu dapper-backports/main Sources
Ign http://ubuntu.cities.uiuc.edu dapper-backports/restricted Sources
Ign http://ubuntu.cities.uiuc.edu dapper-backports/universe Sources
Ign http://ubuntu.cities.uiuc.edu dapper-backports/multiverse Sources
Err http://ubuntu.cities.uiuc.edu dapper-updates/main Packages
  Could not resolve 'ubuntu.cities.uiuc.edu'
Err http://ubuntu.cities.uiuc.edu dapper-updates/restricted Packages
  Could not resolve 'ubuntu.cities.uiuc.edu'
Err http://ubuntu.cities.uiuc.edu dapper-updates/main Sources
  Could not resolve 'ubuntu.cities.uiuc.edu'
Err http://ubuntu.cities.uiuc.edu dapper-updates/restricted Sources
  Could not resolve 'ubuntu.cities.uiuc.edu'
Err http://ubuntu.cities.uiuc.edu dapper/universe Packages
  Could not resolve 'ubuntu.cities.uiuc.edu'
Err http://ubuntu.cities.uiuc.edu dapper/multiverse Packages
  Could not resolve 'ubuntu.cities.uiuc.edu'
Err http://ubuntu.cities.uiuc.edu dapper/universe Sources
  Could not resolve 'ubuntu.cities.uiuc.edu'
Err http://ubuntu.cities.uiuc.edu dapper/multiverse Sources
  Could not resolve 'ubuntu.cities.uiuc.edu'
Err http://ubuntu.cities.uiuc.edu dapper-backports/main Packages
  Could not resolve 'ubuntu.cities.uiuc.edu'
Err http://ubuntu.cities.uiuc.edu dapper-backports/restricted Packages
  Could not resolve 'ubuntu.cities.uiuc.edu'
Err http://ubuntu.cities.uiuc.edu dapper-backports/universe Packages
  Could not resolve 'ubuntu.cities.uiuc.edu'
Err http://ubuntu.cities.uiuc.edu dapper-backports/multiverse Packages
  Could not resolve 'ubuntu.cities.uiuc.edu'
Err http://ubuntu.cities.uiuc.edu dapper-backports/main Sources
  Could not resolve 'ubuntu.cities.uiuc.edu'
Err http://ubuntu.cities.uiuc.edu dapper-backports/restricted Sources
  Could not resolve 'ubuntu.cities.uiuc.edu'
Err http://ubuntu.cities.uiuc.edu dapper-backports/universe Sources
  Could not resolve 'ubuntu.cities.uiuc.edu'
Err http://ubuntu.cities.uiuc.edu dapper-backports/multiverse Sources
  Could not resolve 'ubuntu.cities.uiuc.edu'
Fetched 2B in 2s (1B/s)
Failed to fetch http://ubuntu.cities.uiuc.edu/pub/ubuntu/dists/dapper-updates/Re lease.gpg  Could not resolve 'ubuntu.cities.uiuc.edu'
Failed to fetch http://ubuntu.cities.uiuc.edu/pub/ubuntu/dists/dapper/Release.gp g  Could not resolve 'ubuntu.cities.uiuc.edu'
Failed to fetch http://ubuntu.cities.uiuc.edu/pub/ubuntu/dists/dapper-backports/ Release.gpg  Could not resolve 'ubuntu.cities.uiuc.edu'
Failed to fetch http://ubuntu.cities.uiuc.edu/pub/ubuntu/dists/dapper-updates/ma in/binary-i386/Packages.gz  Could not resolve 'ubuntu.cities.uiuc.edu'
Failed to fetch http://ubuntu.cities.uiuc.edu/pub/ubuntu/dists/dapper-updates/re stricted/binary-i386/Packages.gz  Could not resolve 'ubuntu.cities.uiuc.edu'
Failed to fetch http://ubuntu.cities.uiuc.edu/pub/ubuntu/dists/dapper-updates/ma in/source/Sources.gz  Could not resolve 'ubuntu.cities.uiuc.edu'
Failed to fetch http://ubuntu.cities.uiuc.edu/pub/ubuntu/dists/dapper-updates/re stricted/source/Sources.gz  Could not resolve 'ubuntu.cities.uiuc.edu'
Failed to fetch http://ubuntu.cities.uiuc.edu/pub/ubuntu/dists/dapper/universe/b inary-i386/Packages.gz  Could not resolve 'ubuntu.cities.uiuc.edu'
Failed to fetch http://ubuntu.cities.uiuc.edu/pub/ubuntu/dists/dapper/multiverse /binary-i386/Packages.gz  Could not resolve 'ubuntu.cities.uiuc.edu'
Failed to fetch http://ubuntu.cities.uiuc.edu/pub/ubuntu/dists/dapper/universe/s ource/Sources.gz  Could not resolve 'ubuntu.cities.uiuc.edu'
Failed to fetch http://ubuntu.cities.uiuc.edu/pub/ubuntu/dists/dapper/multiverse /source/Sources.gz  Could not resolve 'ubuntu.cities.uiuc.edu'
Failed to fetch http://ubuntu.cities.uiuc.edu/pub/ubuntu/dists/dapper-backports/ main/binary-i386/Packages.gz  Could not resolve 'ubuntu.cities.uiuc.edu'
Failed to fetch http://ubuntu.cities.uiuc.edu/pub/ubuntu/dists/dapper-backports/ restricted/binary-i386/Packages.gz  Could not resolve 'ubuntu.cities.uiuc.edu'
Failed to fetch http://ubuntu.cities.uiuc.edu/pub/ubuntu/dists/dapper-backports/ universe/binary-i386/Packages.gz  Could not resolve 'ubuntu.cities.uiuc.edu'
Failed to fetch http://ubuntu.cities.uiuc.edu/pub/ubuntu/dists/dapper-backports/ multiverse/binary-i386/Packages.gz  Could not resolve 'ubuntu.cities.uiuc.edu'
Failed to fetch http://ubuntu.cities.uiuc.edu/pub/ubuntu/dists/dapper-backports/ main/source/Sources.gz  Could not resolve 'ubuntu.cities.uiuc.edu'
Failed to fetch http://ubuntu.cities.uiuc.edu/pub/ubuntu/dists/dapper-backports/ restricted/source/Sources.gz  Could not resolve 'ubuntu.cities.uiuc.edu'
Failed to fetch http://ubuntu.cities.uiuc.edu/pub/ubuntu/dists/dapper-backports/ universe/source/Sources.gz  Could not resolve 'ubuntu.cities.uiuc.edu'
Failed to fetch http://ubuntu.cities.uiuc.edu/pub/ubuntu/dists/dapper-backports/ multiverse/source/Sources.gz  Could not resolve 'ubuntu.cities.uiuc.edu'
Reading package lists... Done
E: Some index files failed to download, they have been ignored, or old ones used  instead.
marc@ubuntu:~$ sudo gedit /etc/apt/sources.list