traceroute <host> first-ttl <value>
Displays the route that packets take to a network host.
- Explicitly force IPv4 traceouting. By default, the program will try to resolve the name given, and choose the appropriate protocol automatically. If resolving a host name returns both IPv4 and IPv6 addresses, traceroute will use IPv4.
- Explicitly force IPv6 traceouting. By default, the program will try to resolve the name given, and choose the appropriate protocol automatically. If resolving a host name returns both IPv4 and IPv6 addresses, traceroute will use IPv6.
- A host that is the destination for the trace. The host is specified as a name (if DNS is being used on the network), as an IPv4 or IPv6 address, or as a MAC address (format h:h:h:h:h:h:h:h).
- first-ttl value
- Specifies the first time-to-live value. Defaults to 1.
- The following entries are options. Multiple options can be included on the same command line.
- Performs AS path lookups in routing registries and print results directly after the corresponding addresses.
- Bypasses the normal routing tables and send directly to a host on an attached network. If the host is not on a directly-attached network, an error is returned. This option can be used to ping a local host through an interface that has no route through it.
- Enables socket level debugging.
- gateway address
- Routes the request through a specified gateway.
- Uses ICMP echo for the traceroute probe.
- Shows ICMP extensions (rfc4884). The general form is CLASS/TYPE: followed by a hexadecimal dump.
- interface value
- Specifies the interface that the device must use for traceroute requests.
- interval value
- Specifies the time in seconds between traceroute requests from the device.
- max-ttl value
- Specifies the maximum number of hops for the probe.
- Does not fragment the probe packets.
- num-queries number
- Specifies the number of probe packets per hop. The default is 3.
- port number
- For UDP tracing, specifies the destination port base traceroute will use (the destination port number will be incremented by each probe). For ICMP tracing, specifies the initial icmp sequence value (incremented by each probe too). For TCP specifies just the (constant) destination port to connect.
- seq-queries number
- Specifies the number of sequential probe packets.
- source-addr host
- Specifies an alternative source host by hostname, IPv4 address, or MAC address.
- Uses TCP SYN for the probes.
- tos value
- Marks the packets with the specified Type of Service (TOS) value.
- Displays the timestamp during ping output.
- wait-time value
- Specifies the time (seconds) to wait for a response from the probe. Default is 5 seconds.
Use this command to perform a “traceroute” operation for a network host. This operation uses the IP protocol time-to-live (TTL) field and attempts to elicit an Internet Control Message Protocol (ICMP) TIME_EXCEEDED response from each gateway along the path to a host to track the route that a set of packets follows. It attempts to trace the route an IP packet follows to an Internet host by launching User Datagram Protocol (UDP) probe packets with a small time to live, then listening for an ICMP “Time exceeded” reply from a gateway.
The following example illustrates a traceroute to google.com with the first time-to-live set to 3.
vyatta@vyatta# traceroute google.com first-ttl 3 traceroute to google.com (22.214.171.124), 30 hops max, 60 byte packets 3 76-198-128-2.lightspeed.mtvwca.sbcglobal.net (126.96.36.199) 36.929 ms 38.025 ms 38.016 ms 4 188.8.131.52 (184.108.40.206) 37.998 ms 41.153 ms 40.586 ms 5 220.127.116.11 (18.104.22.168) 43.315 ms 22.214.171.124 (126.96.36.199) 39.053 ms 188.8.131.52 (184.108.40.206) 43.311 ms 6 220.127.116.11 (18.104.22.168) 69.120 ms 69.564 ms 69.086 ms 7 * * * 8 22.214.171.124 (126.96.36.199) 49.860 ms 53.125 ms 39.522 ms 9 188.8.131.52 (184.108.40.206) 35.172 ms 34.588 ms 35.129 ms 10 nuq04s18-in-f7.1e100.net (220.127.116.11) 37.639 ms 36.897 ms 32.858 ms