[root@chronos ~]# yum install mod_ssl
Loaded plugins: refresh-packagekit, security
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package mod_ssl.x86_64 1:2.2.15-39.el6.centos will be installed
--> Processing Dependency: httpd = 2.2.15-39.el6.centos for package: 1:mod_ssl-2
.2.15-39.el6.centos.x86_64
--> Finished Dependency Resolution
Error: Package: 1:mod_ssl-2.2.15-39.el6.centos.x86_64 (base)
           Requires: httpd = 2.2.15-39.el6.centos
           Installed: httpd-2.2.26-2.el5.x86_64 (@CentALT)
               httpd = 2.2.26-2.el5
           Available: httpd-2.2.15-39.el6.centos.x86_64 (base)
               httpd = 2.2.15-39.el6.centos
 You could try using --skip-broken to work around the problem