I have several Debian lenny computers. Two have nearly identical sources.list files. On both, I do regular update/safe-upgrades. On one it always goes smoothly. On the other, much of the time I get the following:
sudo aptitude safe-upgrade Reading package lists... Done Building dependency tree Reading state information... Done Reading extended state information Initializing package states... Done Reading task descriptions... Done The following packages will be upgraded: krb5-clients krb5-ftpd krb5-rsh-server krb5-telnetd krb5-user libimlib2 libkadm55 libkrb53 libpng12-0 libpulse0 xpdf xpdf-common xpdf-reader 13 packages upgraded, 0 newly installed, 0 to remove and 0 not upgraded. Need to get 2906kB of archives. After unpacking 36.9kB will be used. Do you want to continue? [Y/n/?] WARNING: untrusted versions of the following packages will be installed! Untrusted packages could compromise your system's security. You should only proceed with the installation if you are certain that this is what you want to do. krb5-rsh-server krb5-user krb5-ftpd krb5-clients libkrb53 xpdf-reader libpng12-0 libkadm55 xpdf libpulse0 libimlib2 krb5-telnetd xpdf-common Do you want to ignore this warning and proceed anyway? To continue, enter "Yes"; to abort, enter "No": no Abort.
Needless to say, I don't proceed. What is going on? How do I fix it? These are the non-comment lines in the sources.list for this computer:
deb ftp://ftp.debian.org/debian/ lenny main contrib non-free deb-src ftp://ftp.debian.org/debian/ lenny main contrib deb http://security.debian.org/ lenny/updates main contrib non-free