run the following command: rpm -qa | grep el5
Thank you, Jim. That "rpm -e" seemed at first to do the trick. Now more packages are installed under that version.
I then followed the CentOS 4 instructions at http://wiki.centos.org/Repositories/RPMForge but "yum install nagios" gives me the following error.
[root@nagios-server tmp]# yum install nagios Loading "protectbase" plugin Setting up Install Process Setting up repositories Reading repository metadata in from local files 81 packages excluded due to repository protections Parsing package install arguments Resolving Dependencies --> Populating transaction set with selected packages. Please wait. ---> Package nagios.i386 0:2.9-1.el5.rf set to be updated --> Running transaction check --> Processing Dependency: rtld(GNU_HASH) for package: nagios --> Processing Dependency: libc.so.6(GLIBC_2.4) for package: nagios --> Finished Dependency Resolution Error: Missing Dependency: rtld(GNU_HASH) is needed by package nagios Error: Missing Dependency: libc.so.6(GLIBC_2.4) is needed by package nagios [root@nagios-server tmp]#