Use this command to discover the routes that IPv4 or IPv6 packets actually take when traveling to their destination through the network on a hop-by-hop basis. Traceroute continues to provide a synchronous response when initiated from the CLI.
You can specify the source IP address of the traceroute probes. Recall that traceroute works by sending packets that are expected not to reach their final destination, but instead trigger ICMP (Internet Control Message Protocol) error messages back to the source address from each hop along the forward path to the destination. By specifying the source address,you can determine where along the forward path there is no route back to the source address. Note that this is only useful if the route from source to destination and destination to source is symmetric. It would be common, for example, to send a traceroute from an edge router to a target higher in the network using a source address from a host subnet on the edge router. This would test reachability from within the network back to hosts attached to the edge router. Alternatively, one might send a traceroute with an address on a loopback interface as a source to test reachability back to the loopback interface address.
In the CLI, you can specify the source as an IPv4 address, IPv6 address, a virtual router, or as a routing interface. When the source is specified as a routing interface, the traceroute is sent using the primary IPv4 address on the source interface. With SNMP (Simple Network Management Protocol), the source must be specified as an address. The source cannot be specified in the web UI.
200 Series will not accept an incoming packet, such as a traceroute response, that arrives on a routing interface if the packet‘s destination address is on one of the out-of-band management interfaces (service port or network port). Similarly, 200 Series will not accept a packet that arrives on a management interface if the packet‘s destination is an address on a routing interface. Thus, it would be futile to send a traceroute on a management interface using a routing interface address as source, or to send a traceroute on a routing interface using a management interface as source. When sending a traceroute on a routing interface, the source must be that routing interface or another routing interface. When sending a traceroute on a management interface, the source must be on that management interface. For this reason, you cannot specify the source as a management interface or management interface address. When sending a traceroute on a management interface, you should not specify a source address, but instead let the system select the source address from the outgoing interface.
| Default |
|
| Format | traceroute ip-address | [ipv6] {ipv6-address | hostname}} [initTtl initTtl] [maxTtl maxTtl] [maxFail maxFail] [interval interval] [count count] [port port] [size size] [source {ip-address | | ipv6-address | unit/slot/port}] |
| Mode | Privileged EXEC |
Using the following options, you can specify the initial and maximum time-to-live (TTL) in probe packets, the maximum number of failures before termination, the number of probes sent for each TTL, and the size of each probe.
| Parameter | Description |
|---|---|
| ipaddress | The ipaddress value should be a valid IP address. |
| ipv6-address | The ipv6-address value should be a valid IPv6 address. |
| hostname | The hostname value should be a valid hostname. |
| ipv6 | The optional ipv6 keyword can be used before ipv6-address or hostname. Giving the ipv6 keyword before the hostname tries it to resolve to an IPv6 address. |
| initTtl | Use initTtl to specify the initial time-to-live (TTL), the maximum number of router hops between the local and remote system. Range is 0 to 255. |
| maxTtl | Use maxTtle to specify the maximum TTL. Range is 1 to 255. |
| maxFail | Use maxFail to terminate the traceroute after failing to receive a response for this number of consecutive probes. Range is 0 to 255. |
| interval | Use the optional interval parameter to specify the time between probes, in seconds. If a response is not received within this interval, then traceroute considers that probe a failure (printing *) and sends the next probe. If traceroute does receive a response to a probe within this interval, then it sends the next probe immediately. Range is 1 to 60 seconds. |
| count | Use the optional count parameter to specify the number of probes to send for each TTL value. Range is 1 to 10 probes. |
| port | Use the optional port parameter to specify destination UDP port of the probe. This should be an unused port on the remote destination system. Range is 1 to 65535. |
| size | Use the optional size parameter to specify the size, in bytes, of the payload of the Echo Requests sent. Range is 0 to 65507 bytes. |
| source | Use the optional source parameter to specify the source IP address or interface for the traceroute. |
The following are examples show the CLI output for this command.
Successful execution oftraceroute:
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Download EPUB(Extreme 220) (Routing) # traceroute 10.240.10.115 initTtl 1 maxTtl 4 maxFail 0 interval 1 count 3 port 33434 size 43
Traceroute to 10.240.10.115 ,4 hops max 43 byte packets:
1 10.240.4.1 708 msec 41 msec 11 msec
2 10.240.10.115 0 msec 0 msec 0 msec
Hop Count = 1 Last TTL = 2 Test attempt = 6 Test Success = 6
(Extreme 220) (Routing) # traceroute 2001::2 initTtl 1 maxTtl 4 maxFail 0 interval 1 count 3 port 33434 size 43 Traceroute to 2001::2 hops max 43 byte packets: 1 2001::2 708 msec 41 msec 11 msec The above command can also be execute with the optional ipv6 parameter as follows: (Extreme 220) (Routing) # traceroute ipv6 2001::2 initTtl 1 maxTtl 4 maxFail 0 interval 1 count 3 port 33434 size 43
Unsuccessful execution oftraceroute:
(Extreme 220) (Routing) # traceroute 10.40.1.1 initTtl 1 maxFail 0 interval 1 count 3
port 33434 size 43
Traceroute to 10.40.1.1 ,30 hops max 43 byte packets:
1 10.240.4.1 19 msec 18 msec 9 msec
2 10.240.1.252 0 msec 0 msec 1 msec
3 172.31.0.9 277 msec 276 msec 277 msec
4 10.254.1.1 289 msec 327 msec 282 msec
5 10.254.21.2 287 msec 293 msec 296 msec
6 192.168.76.2 290 msec 291 msec 289 msec
7 0.0.0.0 0 msec *
Hop Count = 6 Last TTL = 7 Test attempt = 19 Test Success = 18
(Extreme 220) (Routing)# traceroute 2001::2 initTtl 1 maxFail 0 interval 1 count 3 port 33434 size 43
Traceroute to 2001::2 hops max 43 byte packets:
1 3001::1 708 msec 41 msec 11 msec
2 4001::2 250 msec 200 msec 193 msec
3 5001::3 289 msec 313 msec 278 msec
4 6001::4 651 msec 41 msec 270 msec
5 0 0 msec *
Hop Count = 4 Last TTL = 5 Test attempt = 1 Test Success = 0