Package upgrades and md5 checksum verification

Run upgrades on regular bases and every time a new vulnerability discovered in installed packages:


apt-get update
apt-get dist-upgrade

A new kernel is installed separately from the other packages


apt-cache search kernel-image | grep 686
apt-get install kernel-image-2.6.8-2-686

Verify md5 checksum of downloaded software:


md5sum some_file.tgz

Install dlocate and verify md5 checksum of the files installed with a package:


apt-get install dlocate
dlocate -md5sum tcpd
dlocate -md5check tcpd

Install GNU Privacy Guard (GPG) to check software signature and verifying if files are genuine:

 
gpg --verify ssh-3.2.9.1.tar.gz.sig-gpg ssh-3.2.9.1.tar.gz