wiki.ipfire.org

The community-maintained documentation platform of IPFire

User Tools

Site Tools


addons:traceroute:start

Traceroute

Traceroute is a small shell application which shows the “route” and the routers a datapackege passes to reach a defined target computer. The output of traceroute doesn't show allways the right way, but helps you to find problems inside the network.

Installation

You can install the addon like any other with Pakfire or by using the shell with:

pakfire install -y tracecoute

How does it work?

Traceroute works by increasing the “time-to-live” value of each successive batch of packets sent. The first three packets sent have a time-to-live (TTL) value of one (implying that they are not forwarded by the next router and make only a single hop). The next three packets have a TTL value of 2, and so on. When a packet passes through a host, normally the host decrements the TTL value by one, and forwards the packet to the next host. When a packet with a TTL of one reaches a host, the host discards the packet and sends an ICMP time exceeded (type 11) packet to the sender. The traceroute utility uses these returning packets to produce a list of hosts that the packets have traversed en route to the destination. The three timestamp values returned for each host along the path are the delay (aka latency) values typically in milliseconds (ms) for each packet in the batch. If a packet does not return within the expected timeout window, a star (asterisk) is traditionally printed. Traceroute may not list the real hosts. It indicates that the first host is at one hop, the second host at two hops, etc. IP does not guarantee that all the packets take the same route. Also note that if the host at hop number N does not reply, the hop will be skipped in the output.

Example

Run the following command on the shell of yor IPfire or by using a ssh-connection:

traceroute ipfire.org

You will see smomething like this:

traceroute to ipfire.org (85.88.28.124), 64 hops max, 40 byte packets
1  10.0.0.1 (10.0.0.1)  0.730 ms  0.191 ms  0.251 ms
2  ip-88-153-176-1.unitymediagroup.de (88.153.176.1)  8.834 ms  12.441 ms  10.512 ms
3  1511G-MX960-02-ge-7-1-3.bochum.unity-media.net (80.69.102.173)  7.035 ms  10.943 ms  7.267 ms
4  1211F-MX960-02-xe-0-1-0.dortmund.unity-media.net (80.69.107.66)  8.552 ms  9.196 ms  8.863 ms
5  1411G-MX960-02-xe-1-1-0.neuss.unity-media.net (80.69.107.13)  9.295 ms  12.513 ms  15.112 ms
6  1411G-MX960-01-ae0.neuss.unity-media.net (80.69.107.205)  12.653 ms  7.072 ms  9.295 ms
7  1300-MX960-01-xe-0-3-0.kerpen.unity-media.net (80.69.107.1)  9.686 ms  11.658 ms  9.418 ms
8  * * *
9  cat6509-pg1-g64.netcologne.de (81.173.192.74)  14.332 ms  12.295 ms  14.089 ms
10  core-sto1-vl502.netcologne.de (195.14.195.106)  13.316 ms  15.650 ms  16.145 ms
11  rtkds-sto-g315.netcologne.de (87.79.16.54)  11.531 ms  12.482 ms  13.526 ms
12  195.14.228.42 (195.14.228.42)  13.304 ms  11.015 ms  13.599 ms
13  85.88.28.98 (85.88.28.98)  16.922 ms  14.264 ms  13.593 ms
14  uhweb28124.united-hoster.com (85.88.28.124)  13.226 ms  13.250 ms  13.611 ms
addons/traceroute/start.txt · Last modified: 2018/09/18 21:17 by Jon