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I want to upgrade a server to make sure the recent OpenSSL bug gets patched. So, to check the versions of things I'll be installing, I run apt-get install --dry-run, and see a line like:

Inst openssl [1.0.1-4ubuntu5.11] (1.0.1-4ubuntu5.12 Ubuntu:12.04/precise-updates [amd64])

And I realize I don't know what that means. Does it mean it's going to install 1.0.1-4ubuntu5.11 and that 5.12 is available, or that I'm currently running 5.11 and it'll upgrade to 5.12?

As requested, here's the output of apt-cache policy openssl:

openssl:
  Installed: 1.0.1-4ubuntu5.11
  Candidate: 1.0.1-4ubuntu5.12
  Version table:
     1.0.1-4ubuntu5.12 0
        500 http://archive.ubuntu.com/ubuntu/ precise-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu/ precise-security/main amd64 Packages
 *** 1.0.1-4ubuntu5.11 0
        100 /var/lib/dpkg/status
     1.0.1-4ubuntu3 0
        500 http://archive.ubuntu.com/ubuntu/ precise/main amd64 Packages

... and I think that clears things up. It looks like it'll be grabbing 5.12 from either archive.ubuntu.com or security.ubuntu.com. What's the preceding 500?

Nate
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  • post the output of apt-cache policy openssl – Avinash Raj Apr 08 '14 at 15:35
  • The number 500 is a priority number. In case you want to mix packages from different distributions, there is a priority system that you can use to override the defaults, if you know what you are doing. 500 is just the default priority. It is higher than the installed version (100) so yes, it wants to install version 5.12. – Jos Apr 08 '14 at 15:54

2 Answers2

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The output of apt-get --dry-run means, as you already figured out, that openssl 1.0.1-4ubuntu5.11 is currently installed on your system and that it will be replaced with openssl 1.0.1-4ubuntu5.12 once you run the install command.

The numbers (500 and 100) in the output of apt-cache policy openssl indicate the priority of the given repository. As you can see, there are packages of openssl 1.0.1-4ubuntu5.12 available from two repositories (precise-updates and precise-security), both with a priority of 500. If the precise-security priority were to be 700, apt-get would first try to download the package from that repository.

pille1842
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You're right, it will install openssl 1.0.1-4ubuntu5.12 from http://archive.ubuntu.com.

500 is the priority of the source. See https://wiki.debian.org/AptPreferences

Sylvain Pineau
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