# apt-cache search tcpdump
# apt-cache depends tcpdump
$ apt-cache policy tcpdump
tcpdump:
Installed: 4.0.0-6ubuntu3
Candidate: 4.0.0-6ubuntu3
Version table:
*** 4.0.0-6ubuntu3 0
500 http://us.archive.ubuntu.com/ubuntu/ lucid/main Packages
100 /var/lib/dpkg/status