To use the inter-satellite sync feature, you must first ensure that you have it enabled. Make sure that the /etc/rhn/rhn.conf contains the following line:

disable_iss=0

In the same file is the variable:

allowed_iss_slaves=

By default, no slave Satellites are specified to sync from the master server, so you must enter the hostname of each slave Satellite server, separated by commas. For example:

allowed_iss_slaves=slave1.satellite.example.org,slave2.satellite.example.org

Once you finished configuring the rhn.conf file, restart the httpd service by issuing the following command:

service httpd restart