Commands After  completing each step, put a '√' or 'x' in the completed box Objectives Within OSPF or other routing protocol, it is critical within troubleshooting to understand the tools that are available i.e. the best tools to use are show and debug

1. Open up the packet tracer topology . Should look like the following. On any of the configured routers you will execute the following show and debug commands. We will look at the commands from two perspectives 

1. How they help troubleshoot 

2. What data they display when executed. 

Show ip route ospf command Help troubleshoot • Missing routes • Summarization issues • Filtering problems • General troubleshooting Displays the following data • OSPF routes from neighbors i.e. route been received from neighbors • Administrative distance • Cumulative cost metric to reach a particular subnet • Route source/interface Now execute the command on one of the routers in your topology. Show ip ospf interface command Help troubleshoot • Neighbor relationships • Local configuration issues • Routing problems Displays the following data • Interfaces participating in OSPF i.e. shows all the interfaces that have been configured and are participating in OSPF. • Network type (s) e.g. broadcast, non-broadcast etc. • Neighbor count • Authentication type • Timer values show ip ospf neighbor command Helpful in troubleshooting • Neighbor relationships • Local configuration issues Displays the following data • Active fully adjacent neighbors • Router ID of neighbors • IP address/interface of neighbors • Dead time of neighbors • Neighbor state/DR state e.g. full (anything other than full could be an potential issue). Also shows state of designated router and backup designated router that it maybe connected to e.g. if it's the DR it will say Full/DR, if its the backup designated router it will say Full/BDR and if its just another device that's neither, it will just say full/DR other (meaning that its neither the DR or BDR) This command shows us the neighbor id of Routers 1 and 2 show ip ospf database command Helpful in troubleshooting • Missing routes • Filtering problems • General troubleshooting Displays the following data • Display entire contents of link state database • LSA types per area e.g. 1, 2, 3, 4, 5 for example • Advertising router i.e. router that is advertising that particular network • Link ID (subnet) • Age that's on the routing table Show ip route command show ip protocols command (very broad show command) Helpful in troubleshooting • neighbor relationships e.g. neighbors/gateways that you might have been expecting (will show you this) • missing routes • Summarization issues • Filtering problems Displays the following data • OSPF status and process-id • Area types configured e.g. normal, stub etc. • Protocols being redistributed • Networks being advertised • Neighbors/gateways Show ip ospf border-routers commands Helpful in troubleshooting • Missing routes • Filtering problems • General troubleshooting e.g. if an external router is missing, this command will tell you if something is not right with the ABR or ASBR Displays the following data • Router ID • Advertising router • Area the router belongs to • Whether ABR (Area Border Router) or ASBR (Autonomous System Boundary Router) • Cost to reach Show ip ospf command Helpful in troubleshooting • Missing routes • Filtering problems • General troubleshooting Displays the following • OSPF process-id • Configured areas • Number/types or areas/ranges • Configured area authentication • Number of times SPF algorithm executed e.g. if you look at a particular area and see a very high number of SPF calculations then it could be a flapping router or an interface with an issue • Interfaces per area on router Debug commands can also be useful in determining the cause of particular issues debug ip ospf events Debugging network events i.e. things that are going on with the network from an OSPF standpoint Helpful in troubleshooting • Routing update issues • Convergence issues • Interface flapping debug ip ospf adj Debugging neighbor adjacencies Helpful in troubleshooting • Neighbor relationships • Routing update issues • Stub router problems This command is not supported in packet tracer debug ip spf hello Debugging neighbor adjacencies i.e. how often the hellos are happening and what's involved with that Helpful in troubleshooting • Neighbor relationships • Configuration issues • DR/BDR election problems (as hellos are using during this election process) This command is not supported in packet tracer