Telnet to the router or connect via the console and enter into enable mode.
Enter the following commands from the enable prompt on the router.
Logging Facility Local7 (or any other facility you want to allocate for this router.)
Logging [IP Address or Hostname of machine running Kiwi Syslog Server]
Another useful command is logging source-interface which first appeared in IOS v11.2. According to Cisco, a syslog message contains the IP address of the interface it uses to leave the router. The logging source-interface command specifies that syslog packets contain the IP address of a particular interface, regardless of which interface the packet uses to exit the router.
* The logging source-interface command MUST be used on some versions of IOS due to a bug. If the command is not used the Syslog messages sent have an invalid UDP checksum and are dropped by Winsock before the Kiwi Syslog Server gets to see them.
More information on Cisco logging commands can be found on the Cisco's website.