# apt-get install linux-headers-server
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
   linux-headers-3.2.0-49 (3.2.0-49.75)
   linux-headers-3.2.0-49-generic (3.2.0-49.75)
   linux-image-3.2.0-49-generic (3.2.0-49.75)
   linux-image-server (3.2.0.49.59)
   linux-server (3.2.0.49.59)
Suggested packages:
   fdutils (5.5-20060227-5)
   linux-doc-3.2.0 ()
   linux-source-3.2.0 (3.2.0-49.75)
   linux-tools (3.2.0.49.59)
The following NEW packages will be installed:
   linux-headers-3.2.0-49 (3.2.0-49.75)
   linux-headers-3.2.0-49-generic (3.2.0-49.75)
   linux-image-3.2.0-49-generic (3.2.0-49.75)
The following packages will be upgraded:
   linux-headers-server (3.2.0.48.58 => 3.2.0.49.59)
   linux-image-server (3.2.0.48.58 => 3.2.0.49.59)
   linux-server (3.2.0.48.58 => 3.2.0.49.59)
3 upgraded, 3 newly installed, 0 to remove and 0 not upgraded.
Need to get 51.2 MB of archives.
After this operation, 217 MB of additional disk space will be used.
Do you want to continue [Y/n]? y
WARNING: The following packages cannot be authenticated!
  linux-image-3.2.0-49-generic linux-headers-3.2.0-49
  linux-headers-3.2.0-49-generic linux-server linux-image-server
  linux-headers-server