If the exception dump command is not configured, the router reloads without generating a core dump. The following example configures the router to monitor the free memory. If it falls below 250,000 bytes, it will dump the core and reload. You can test core dumps by using the write core privileged EXEC command. This command causes the router to generate a core dump without reloading and is useful if the router is malfunctioning but has not crashed.
Caution Use the write core command only under the direction of a technical support representative.
Creating a core dump while the router is functioning in a network can disrupt network operation. The resulting binary file, which is very large, must be transferred to a TFTP, FTP, or rcp server and subsequently interpreted by technical personnel who have access to source code and detailed memory maps. Depending on your TFTP server, you might need to create an empty target file to which the router can write the core. Output from these commands provides the support representative with important information about the state of your router when it failed. The show running-config command displays the current running configuration of the router.