ubuntu 安装ssh-server时出现错误：openssh-server: Depends: openssh-client (= 1:5.3p1-3ubuntu3) but 1:5.3p1-3ubuntu4 is to be installed

错误如下：

tiger@ubuntu:~/Desktop/work$ sudo apt-get install openssh-server
[sudo] password for tiger:
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
  openssh-server: Depends: openssh-client (= :.3p1-3ubuntu3) but :.3p1-3ubuntu4 is to be installed
E: Broken packages

输入如下命令即可：

sudo apt-get install openssh-client=1:5.3p1-3ubuntu3

然后出现下面的执行过程：

Reading package lists... Done
Building dependency tree
Reading state information... Done
Suggested packages:
  libpam-ssh keychain openssh-blacklist openssh-blacklist-extra
The following packages will be DOWNGRADED:
  openssh-client
 upgraded,  newly installed,  downgraded,  to remove and  not upgraded.
Need to get 761kB of archives.
After this operation, 0B of additional disk space will be used.
Do you want to continue [Y/n]? y
Get: http://us.archive.ubuntu.com/ubuntu/ lucid/main openssh-client 1:5.3p1-3ubuntu3 [761kB]
Fetched 761kB in 1min 48s (,003B/s)
dpkg: warning: downgrading openssh-client from :.3p1-3ubuntu4 to :.3p1-3ubuntu3.
(Reading database ...  files and directories currently installed.)
Preparing to replace openssh-client :.3p1-3ubuntu4 (using .../openssh-client_1%3a5.3p1-3ubuntu3_i386.deb) ...
Unpacking replacement openssh-client ...
Processing triggers for man-db ...
Setting up openssh-client (:.3p1-3ubuntu3) ...

tiger@ubuntu:~/Desktop/work$ sudo apt-get install openssh-server
Reading package lists... Done
Building dependency tree
Reading state information... Done
Suggested packages:
  rssh molly-guard openssh-blacklist openssh-blacklist-extra
The following NEW packages will be installed:
  openssh-server
 upgraded,  newly installed,  to remove and  not upgraded.
Need to get 285kB of archives.
After this operation, 778kB of additional disk space will be used.
Get: http://us.archive.ubuntu.com/ubuntu/ lucid/main openssh-server 1:5.3p1-3ubuntu3 [285kB]
Fetched 285kB in 1min 13s (,866B/s)
Preconfiguring packages ...
Selecting previously deselected package openssh-server.
(Reading database ...  files and directories currently installed.)
Unpacking openssh-server (from .../openssh-server_1%3a5.3p1-3ubuntu3_i386.deb) ...
Processing triggers for ureadahead ...
ureadahead will be reprofiled on next reboot
Processing triggers for ufw ...
Processing triggers for man-db ...
Setting up openssh-server (:.3p1-3ubuntu3) ...
Creating SSH2 RSA key; this may take some time ...
Creating SSH2 DSA key; this may take some time ...
 * Stopping OpenBSD Secure Shell server sshd                                                           [ OK ]
ssh start/running, process 

tiger@ubuntu:~/Desktop/work$