1.118 NWTrace

Purpose

Use at the server console to print the route that packets take to the network host.

NWTrace utilizes the IP Protoco time-to-live field and attempts to elicit an ICMP_TIME_EXCEEDED response from each of the gateways along the path to a host, to track the route the packets follow. The only mandatory parameter is the destination hostname or IP address. The default probe datagram length is 40 bytes, but this can be increased by specifying a packet length (in bytes) after the destination hostname.

Syntax

NWtrace [-Snv] [-M min_ttl] [-m max_ttl] [-q nqueries] [-s src_addr] [-w wait_time] host [packetlen]

Option

Use To

-S

Print a summary of how many probes were not answered for each hop.

-n

Print hop addresses numerically only rather than numerically and symbolically (saves a nameserver address-to-name lookup for each gateway found on the path.)

-v

Get verbose output. The received ICMP packets other than TIME_EXCEEDED and UNREACHABLEs are listed.

-M min_ttl

Set the initial time-to-live value used in outgoing probe packets.

Default: 1 (start with the first hop)

-m max_ttl

Set the maximum time-to-live (max number of hops) used in outgoing probe packets.

Default: 30 (default max_ttl used for TCP connections)

-q nqueries

Set the number of probes per hop.

Default: 3

-s src_addr

Use the specified IP address (that must be given as an IP number, not a hostname) as the source address in outgoing probe packets. On hosts with more than one IP address, this option can be used to force the source address to be other than the IP address of the interface the probe that the packet is sent on. If the IP address is not one of this machine’s interface addresses, an error is returned and nothing is sent.

-w wait_time

Set the time (in seconds) to wait for a response to a probe.

Default: 5