Creating Core Dumps - Internetworking Troubleshooting - page 797

APPENDIX A

Creating Core Dumps

When a router crashes, it is sometimes useful to obtain a full copy of the memory image (called a core
dump ) to identify the cause of the crash. Core dumps are generally very useful to your technical support
representative. Not all crash types will produce a core dump. The different crash types are discussed in
more details in Appendix B, “Memory Maps.”

Use the commands discussed in this appendix 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.

Caution

Basic Setup

Four basic ways exist for setting up the router to generate a core dump:

Using Trivial File Transfer Protocol (TFTP) •

Using File Transfer Protocol (FTP) •

Using remote copy protocol (rcp)

•

Using a Flash disk

•

Using TFTP

If TFTP is used to dump the core file to the TFTP server, the router will dump only the first 16 MB of
the core file. This is a limitation of most TFTP applications. Therefore, if your router's main memory is
more than 16 MB, do not use TFTP.
The following is the router configuration needed for getting a core dump using TFTP:

exception dump a.b.c.d

Here, a.b.c.d is the IP address of the TFTP server.
The core dump is written to a file named hostname -core on the TFTP server, where hostname is the name
of the router. You can change the name of the core file by adding the exception core-file filename
configuration command.