Cisco IP Routing Protocols: Trouble Shooting Techniques (Charles River Media Networking/Security)

The ping command is a diagnostic tool to test connectivity of hosts in a TCP/IP network and isolate TCP/IP network problems.

The user exec mode is used to perform a simple TCP/IP network connectivity test.

Parameters of the ping command in the user exec mode are protocol, host name, and address.

The privilege exec mode, also known as an extended ping, is used to perform a detailed check of TCP/IP network connectivity.

Different parameters of the ping command in the privilege exec mode are protocol, target IP address, repeat count [5], datagram size [100], timeout in seconds [2], and extended commands [n].

The trace command is a diagnostic tool to trace the path between two hosts to locate any connectivity problems.

The parameters of the trace command are host name and host address.

The trace command ends when the destination host replies on receipt of a packet, the maximum TTL value of 30 is exceeded, or a user interrupts the trace command by using the escape sequence.

The show command is a diagnostic tool to determine the exact cause of a performance slowdown in a TCP/IP network.

The show ip route command displays records in the IP routing table.

The show ip ospf command displays detailed information regarding OSPF ports and interfaces.

The show ip ospf interface command displays information regarding the interfaces on which OSPF is running .

The show ip ospf neighbor command is used to display information regarding the neighboring routers connected with OSPF.

The show ip access-list command is used to display information regarding specific or all current IP access lists in the 1 to 99 range.

The show ip arp command displays information present in the router’s ARP cache.

The show ip protocols command displays information regarding IP routing protocols that are executed on the router.

The show ip traffic command displays information collected by the router regarding IP traffic.

The debug ip rip command displays information regarding RIP routing transactions that are sent by a serial interface.

The debug ip icmp command enables you to determine if the router is sending and receiving ICMP messages.

The debug ip packet command displays all the IP debugging information and IP security options.

The debug arp command checks the flow of data at the ARP.

RIP takes a longer time to converge than IGRP.

To counter unsecured exchange of routing information and routing loops, use the default-metric or redistribute protocol metric command.

To check if a TCP/IP network is working properly, execute the loopback ping command.

Use the Tracert tool to trace a TCP/IP packet crossing its way to the destination.