3Com 3500 manual Ip traceRoute, Valid Minimum Abbreviation

478CHAPTER 16: INTERNET PROTOCOL (IP)

ip traceRoute

✓3500

✓9000

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For CoreBuilder 9000: Applies to Layer 3 switching modules only.

Traces a route to a destination using the default traceRoute options.

Valid Minimum Abbreviation

ip t

Important Considerations

■TraceRoute information includes all of the nodes in the network through which a packet passes to get from its origin to its destination. It uses the IP time-to-live (TTL) field in UDP probe packets to elicit an Internet Control Message Protocol (ICMP) Time Exceeded message from each gateway to a host.

■To change the default traceRoute options, use ip advancedTraceRoute. (The command description for “ip advancedTraceRoute” lists the default traceRoute options.)

■You can either supply the host name or IP address as part of the command string, or you can supply the information at the prompt.

■When you specify a host name, the host name and its associated IP address must be configured on a network name server. Also, you must add the IP address on the name server to the list of name server addresses that are associated with the network domain name. See “ip dns domainName” earlier in this chapter for more information.

■To track the route of an IP packet, traceRoute launches User Datagram Protocol (UDP) probe packets with a small TTL value and then listens for an ICMP Time Exceeded reply from a gateway. Probes start with a small TTL of 1 and increase the value by 1 until one of the following events occurs:

■The system receives a Port Unreachable message, which indicates that the packet reached the host.

■The probe exceeds the maximum number of hops (default 30).