OSPF Network Design Solutions
OSPF debug Commands
The debug privileged EXEC commands can provide a wealth of information about the traffic and events being seen (or not seen) to include but not limited to, interface traffic, error messages generated by nodes on the network, protocol-specific diagnostic packets, and other useful troubleshooting data.
Notes: Exercise extreme care when using debug commands. Many of these commands are processor-intensive and can cause serious network problems (such as degraded performance or loss of connectivity) if they are enabled on an already heavily loaded router. When you finish using a debug command, remember to disable it with its specific no debug command (or use the no debug all command to turn off all debugging). When to Use debug Commands Only use debug commands to isolate problems, not to monitor normal network operation. Because the high overhead of debug commands can disrupt router operation, you should use debug commands only when you are looking for specific types of traffic or problems and have narrowed your problems to a likely subset of causes. There are a quite a few debug commands available to you. The following is an example of only the IP-based debug commands that you might use. OSPF_Router# debug ip ? bgp BGP information cache IP cache operations cgmp CGMP protocol activity dvmrp DVMRP protocol activity egp EGP information eigrp IP-EIGRP information error IP error debugging http HTTP connections icmp ICMP transactions igmp IGMP protocol activity igrp IGRP information mcache IP multicast cache operations mobile Mobility protocols mpacket IP multicast packet debugging mrouting IP multicast routing table activity ospf OSPF information packet General IP debugging and IPSO security transactions peer IP peer address activity pim PIM protocol activity policy Policy routing rip RIP protocol transactions routing Routing table events sd Session Directory (SD) security IP security options tcp TCP information udp UDP based transactions The format of the output varies with each different debug command:
How to Use debug Commands Adhering to the following procedure minimizes the load created by using debug commands because the console port no longer has to generate character-by-character processor interrupts. To minimize the negative impact on your router of using debug commands, follow this procedure:
Complete OSPF debug Commands This book refers to specific debug commands that are useful when troubleshooting OSPF-specific related problems. Complete details regarding the function and output of debug commands are provided in Cisco’s Debug Command Reference publication.
TIPS: debug is a useful command that has many different options available for its use. It also provides you with a lot of information on what is going on within a router. However, it also can hurt the routing processes and normal operation of the router, so use it wisely. The following is a list of the different types of debug commands:
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