3Com 4500 50-PORT, 4500 PWR 50-PORT, 4500 PWR 26-PORT, 4500 26-PORT manual Port is, SW4500tracert

360CHAPTER 12: USING SYSTEM MANAGEMENT COMMANDS

Description

Use the tracert command to check the reachability of network connection and troubleshoot the network. User can test gateways passed by the packets transmitted from the host to the destination.

By default, when the parameters are not specified,

first-TTL is 1,

max-TTL is 30,

port is 33434,

nqueries is 3 and

timeout is 5s.

The tracert command sends a packet with TTL 1, and the first hop will send an ICMP error message back to indicate this packet cannot be transmitted (because of TTL timeout). Then this packet will be sent again with TTL 2, and the second hop will indicate a TTL timeout error. Perform this operation repeatedly till reaching the destination. These processes are operated to record the source address of each ICMP TTL timeout so as to provide a path to the destination for an IP packet.

After the ping command finds some error on the network, perform tracert to locate the error.

The output of the tracert command includes IP address of all the gateways to the destination. If a certain gateway times out, output "***".

Example

Test the gateways passed by the packets to the destination host at 18.26.0.115.

<SW4500>tracert 18.26.0.115

tracert to allspice.lcs.mit.edu (18.26.0.115), 30 hops max 1 helios.ee.lbl.gov (128.3.112.1) 0 ms 0 ms 0 ms

2 lilac-dmc.Berkeley.EDU (128.32.216.1) 19 ms 19 ms 19 ms 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 19 ms 19 ms

4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 19 ms 39 ms 39 ms 5 ccn-nerif22.Berkeley.EDU (128.32.168.22) 20 ms 39 ms 39 ms 6 128.32.197.4 (128.32.197.4) 59 ms 119 ms 39 ms

7 131.119.2.5 (131.119.2.5) 59 ms 59 ms 39 ms

8 129.140.70.13 (129.140.70.13) 80 ms 79 ms 99 ms

9 129.140.71.6 (129.140.71.6) 139 ms 139 ms 159 ms

10 129.140.81.7 (129.140.81.7) 199 ms 180 ms 300 ms

11 129.140.72.17 (129.140.72.17) 300 ms 239 ms 239 ms

12 * * *

13 128.121.54.72 (128.121.54.72) 259 ms 499 ms 279 ms

14 * * *

15 * * *

16 * * *

17 * * *

18 ALLSPICE.LCS.MIT.EDU (18.26.0.115) 339 ms 279 ms 279 ms