Linux commands must be learned every day (55) traceroute command _linux Shell

The relevant knowledge about the Linux traceroute command is as follows:

Through traceroute we can know the information from your computer to the Internet on the other end of the host is what path to go. Of course the path to a certain same destination (destination) may be different every time a packet is reached by a certain same starting point (source), but basically the route is the same for most of the time. Linux, which we call Traceroute, is tracert in MS Windows. Traceroute measures how long it takes to send a small packet to the destination device until it returns. Each device on a path traceroute 3 times. The output includes the time of each test (MS) and the name of the device (if any) and its IP address.
In most cases, we will execute the command line directly under the Linux host system:

traceroute hostname

Under Windows System is the command to execute tracert:
tracert hostname

1. Command format:

traceroute[parameters [Host]

2. Command function:

The traceroute directive allows you to track network packet routing, the default packet size is 40Bytes, users can set separate.
Specific parameter format: traceroute [-dflnrvx][-f< survival value >][-g< gateway ...] [-i< network Interface ";] [-m< survival Value "] [-p< communication port;] [-s< source Address;] [-t< service type; [-w< timeout number of seconds [Host name or IP address] [Packet size]

3. Command parameters:

-D uses the socket-level debugging feature.
-F Sets the size of the live value TTL for the first detection packet.
-F setting does not leave the fault position.
-G Sets the source routing gateway, up to 8.
-I sends out packets using the specified network interface.
-I replaces UDP data information with an ICMP response.
-M sets the size of the maximum surviving value TTL for the detection packet.
-N uses the IP address directly instead of the host name.
-P Sets the communication port for the UDP transport protocol.
-R ignores the normal routing table and sends the packet directly to the remote host.
-S sets the IP address of the packet to be sent by the local host.
-T sets the TOS value for the instrumentation packet.
-V details the execution of the instruction.
-W Sets the time to wait for the remote host to return.
-X turns on or off the correctness test of the packet.

4. Use examples:

Instance 1:traceroute usage simple, most common usage

Command:
Traceroute www.baidu.com

Output:

[Root@localhost ~]# traceroute www.baidu.com
Traceroute to Www.baidu.com (61.135.169.125), hops max, byte packets
1 192.168.74.2 (192.168.74.2) 2.606 ms 2.771 ms 2.950 ms
2 211.151.56.57 (211.151.56.57) 0.596 ms 0.598 ms 0.591 ms
3 211.151.227.206 (211.151.227.206) 0.546 ms 0.544 ms 0.538 ms
4 210.77.139.145 (210.77.139.145) 0.710 ms 0.748 ms 0.801 ms
5 202.106.42.101 (202.106.42.101) 6.759 ms 6.945 ms 7.107 ms
6 61.148.154.97 (61.148.154.97) 718.908 ms * BT-228-025.BTA.NET.CN (202.106.228.25) 5.177 ms
7 124.65.58.213 (124.65.58.213) 4.343 ms 4.336 ms 4.367 ms
8 202.106.35.190 (202.106.35.190) 1.795 Ms 61.148.156.138 (61.148.156.138) 1.899 Ms 1.951 ms
9 * * *
30 * * *
[Root@localhost ~]#

Description

Record by serial number starting from 1, each record is a hop, each jump represents a gateway, we see each row has three time, the unit is MS, in fact, is the default parameter-Q. The time returned by the gateway response after the probe packet sent three packets to each gateway, and if you use Traceroute-q 4 www.58.com, send 4 packets to each gateway.

Sometimes when we traceroute a host, we see that there are rows that are indicated by an asterisk. As a result, it is possible that the firewall has blocked the return information of the ICMP, so we have not got any relevant data packets to return the data.

Sometimes we have a long delay at a certain gateway, it is possible that a gateway is more blocked, or the physical device itself is probably the reason. Of course, if a DNS problem, can not resolve the host name, domain name, there will be long delay phenomenon; You can add the-n parameter to avoid DNS resolution and output data in IP format.

If in the LAN between different network segments, we can through traceroute to troubleshoot the problem, is the host problem or gateway problem. If we encounter a problem with a remote access to a server, we use the gateway of the Traceroute tracking packet and submit it to the IDC service provider to help solve the problem. But at the moment it seems more difficult to solve the problem at home, where we find the problem, IDC service providers can not help us solve.

Instance 2: Hop count setting

Command:

Traceroute-m www.baidu.com

Output:

[Root@localhost ~]# traceroute-m www.baidu.com
Traceroute to Www.baidu.com (61.135.169.105), hops max, byte packets
1 192.168.74.2 (192.168.74.2) 1.534 ms 1.775 ms 1.961 ms
2 211.151.56.1 (211.151.56.1) 0.508 ms 0.514 ms 0.507 ms
3 211.151.227.206 (211.151.227.206) 0.571 ms 0.558 ms 0.550 ms
4 210.77.139.145 (210.77.139.145) 0.708 ms 0.729 ms 0.785 ms
5 202.106.42.101 (202.106.42.101) 7.978 ms 8.155 ms 8.311 ms
6 bt-228-037.bta.net.cn (202.106.228.37) 772.460 Ms Bt-228-025.bta.net.cn (202.106.228.25) 2.152 Ms 61.148.154.97 (61.1 48.154.97) 772.107 ms
7 124.65.58.221 (124.65.58.221) 4.875 Ms 61.148.146.29 (61.148.146.29) 2.124 Ms 124.65.58.221 (124.65.58.221) 4.854 ms
8 123.126.6.198 (123.126.6.198) 2.944 Ms 61.148.156.6 (61.148.156.6) 3.505 Ms 123.126.6.198 (123.126.6.198) 2.885 ms
9 * * *
10 * * *
[Root@localhost ~]#

Description

Example 3: Display IP address, not check host name

Command:

Traceroute-n www.baidu.com

Output:

[Root@localhost ~]# traceroute-n www.baidu.com
Traceroute to Www.baidu.com (61.135.169.125), hops max, byte packets
1 211.151.74.2 5.430 ms 5.636 ms 5.802 ms
2 211.151.56.57 0.627 ms 0.625 ms 0.617 ms
3 211.151.227.206 0.575 ms 0.584 ms 0.576 ms
4 210.77.139.145 0.703 ms 0.754 ms 0.806 ms
5 202.106.42.101 23.683 ms 23.869 ms 23.998 ms
6 202.106.228.37 247.101 MS * *
7 61.148.146.29 5.256 Ms 124.65.58.213 4.386 MS 4.373 ms
8 202.106.35.190 1.610 Ms 61.148.156.138 1.786 Ms 61.148.3.34 2.089 MS
9 * * *
30 * * *
[Root@localhost ~]# traceroute www.baidu.com
Traceroute to Www.baidu.com (61.135.169.125), hops max, byte packets
1 211.151.74.2 (211.151.74.2) 4.671 ms 4.865 ms 5.055 ms
2 211.151.56.57 (211.151.56.57) 0.619 ms 0.618 ms 0.612 ms
3 211.151.227.206 (211.151.227.206) 0.620 ms 0.642 ms 0.636 ms
4 210.77.139.145 (210.77.139.145) 0.720 ms 0.772 ms 0.816 ms
5 202.106.42.101 (202.106.42.101) 7.667 ms 7.910 ms 8.012 ms
6 bt-228-025.bta.net.cn (202.106.228.25) 2.965 Ms 2.440 Ms 61.148.154.97 (61.148.154.97) 431.337 ms
7 124.65.58.213 (124.65.58.213) 5.134 ms 5.124 ms 5.044 ms
8 202.106.35.190 (202.106.35.190) 1.917 ms 2.052 ms 2.059 ms
9 * * *
30 * * *
[Root@localhost ~]#

Description

Instance 4: Basic UDP port settings used by the probe package 6888

Command:

Traceroute-p 6888 www.baidu.com

Output:

[Root@localhost ~]# traceroute-p 6888 www.baidu.com
Traceroute to Www.baidu.com (220.181.111.147), hops max, byte packets
1 211.151.74.2 (211.151.74.2) 4.927 ms 5.121 ms 5.298 ms
2 211.151.56.1 (211.151.56.1) 0.500 ms 0.499 ms 0.509 ms
3 211.151.224.90 (211.151.224.90) 0.637 ms 0.631 ms 0.641 ms
4 * * *
5 220.181.70.98 (220.181.70.98) 5.050 ms 5.313 ms 5.596 ms
6 220.181.17.94 (220.181.17.94) 1.665 MS! X * *
[Root@localhost ~]#

Description

Example 5: Set the number of probe packets to a value of 4

Command:

Traceroute-q 4 www.baidu.com

Output:

[Root@localhost ~]# traceroute-q 4 www.baidu.com
Traceroute to Www.baidu.com (61.135.169.125), hops max, byte packets
1 211.151.74.2 (211.151.74.2) 40.633 ms 40.819 ms 41.004 ms 41.188 ms
2 211.151.56.57 (211.151.56.57) 0.637 ms 0.633 ms 0.627 ms 0.619 ms
3 211.151.227.206 (211.151.227.206) 0.505 ms 0.580 ms 0.571 ms 0.569 ms
4 210.77.139.145 (210.77.139.145) 0.753 ms 0.800 ms 0.853 ms 0.904 ms
5 202.106.42.101 (202.106.42.101) 7.449 ms 7.543 ms 7.738 ms 7.893 ms
6 61.148.154.97 (61.148.154.97) 316.817 Ms Bt-228-025.bta.net.cn (202.106.228.25) 3.695 ms 3.672 MS *
7 124.65.58.213 (124.65.58.213) 3.056 ms 2.993 ms 2.960 ms 61.148.146.29 (61.148.146.29) 2.837 ms
8 61.148.3.34 (61.148.3.34) 2.179 ms 2.295 ms 2.442 ms 202.106.35.190 (202.106.35.190) 7.136 ms
9 * * * *
30 * * * *
[Root@localhost ~]#

Description

Example 6: Bypassing the normal routing table and sending it directly to a network-attached host

Command:

Traceroute-r www.baidu.com

Output:

[Root@localhost ~]# traceroute-r www.baidu.com
Traceroute to Www.baidu.com (61.135.169.125), hops max, byte packets
Connect: The network can not reach
[Root@localhost ~]#

Description

Example 7: Set the wait response time for the outbound probe pack to 3 seconds

Command:

Traceroute-w 3 www.baidu.com

Output:

[Root@localhost ~]# traceroute-w 3 www.baidu.com
Traceroute to Www.baidu.com (61.135.169.105), hops max, byte packets
1 211.151.74.2 (211.151.74.2) 2.306 ms 2.469 ms 2.650 ms
2 211.151.56.1 (211.151.56.1) 0.621 ms 0.613 ms 0.603 ms
3 211.151.227.206 (211.151.227.206) 0.557 ms 0.560 ms 0.552 ms
4 210.77.139.145 (210.77.139.145) 0.708 ms 0.761 ms 0.817 ms
5 202.106.42.101 (202.106.42.101) 7.520 ms 7.774 ms 7.902 ms
6 bt-228-025.bta.net.cn (202.106.228.25) 2.890 Ms 2.369 Ms 61.148.154.97 (61.148.154.97) 471.961 ms
7 124.65.58.221 (124.65.58.221) 4.490 ms 4.483 ms 4.472 ms
8 123.126.6.198 (123.126.6.198) 2.948 Ms 61.148.156.6 (61.148.156.6) 7.688 Ms 7.756 ms
9 * * *
30 * * *
[Root@localhost ~]#

Description

Traceroute's working principle:
The simplest basic usage of traceroute is: traceroute hostname
The Traceroute program is designed to take advantage of the TTL (field) of ICMP and IP headers. First, Traceroute sends out a TTL is 1 IP datagram (in fact, each send out for 3 40 bytes of packets, including the source address, the destination address and packet issued by the time tag) to the destination, when the path of the first router (router) received this datagram, It will reduce the TTL by 1. At this point, the TTL becomes 0, so the router discards this datagram and sends back a "ICMP time exceeded" message (including the source address of the IP packet, all the contents of the IP packet and the IP address of the router), traceroute after receiving this message, Know that this router exists on this path, then traceroute another TTL is 2 datagram, found the 2nd router ... traceroute each time you send a datagram TTL plus one to find another router, This repetitive movement continues until a datagram arrives at the destination. When datagram arrives at the destination, the host does not send back the ICMP Time exceeded message because it is already the destination, so how did Traceroute know where the destination arrived?
Traceroute when sending a UDP datagrams to a destination, the port number that it chooses to deliver is one that the general application will not use (more than 30000), so when the UDP datagram arrives at the destination, the host sends back a "ICMP The message of Port unreachable", and when Traceroute received the news, he knew the destination had arrived. So there is no daemon program on the server side of Traceroute.
traceroute extracts the IP address of the ICMP TTL expiration message device and makes a domain name resolution. Each time, the traceroute prints out a series of data, including the domain name and IP address of the routed device it passes through, and the three packets take time to go back and forth every time.

Windows tracert:

Format:

tracert [-d] [-h maximum_hops] [-j host-list] [-w timeout] Target_name

Parameter description:

tracert [-d] [-h maximum_hops] [-j computer-list] [-w timeout] Target_name

The diagnostic utility sends an Internet control Information Protocol (CMP) response message to destinations that has different lifetimes (TL) to determine the route to the destination. Each router on the path has to reduce its TTL value by at least 1 before forwarding the ICMP response message, so the TTL is a valid jump count. When the TTL value of a message is reduced to 0 o'clock, the router sends back ICMP timeout information to the source system. Tracert can determine the route by sending the first response message with a TTL of 1 and adding the TTL value 1 at a time in subsequent sends until the target responds or reaches the maximum TTL value. You can determine the router by checking the ICMP timeout (IME exceeded) information sent back by the intermediate router. Note that some routers "silently" discard expired messages for lifetime (TLS) and are not valid for tracert.

Parameters:

-d Specifies that the address is not resolved on the computer name.
-h maximum_hops Specifies the maximum number of jumps to find a target.
-jcomputer-list Specifies loose source routing in the computer-list.
-w timeout waits for the number of milliseconds specified by timeout for each reply.
Target_name the name of the target computer.

Instance:

C:\users\administrator>tracert www.58.com
Tracing route to www.58.com [221.187.111.30]
Over a maximum of hops:
1 1 ms 1 ms 1 ms 10.58.156.1
2 1 ms <1 ms <1 ms 10.10.10.1
3 1 ms 1 ms 1 ms 211.103.193.129
4 2 ms 2 ms 2 ms 10.255.109.129
5 1 ms 1 ms 3 ms 124.205.98.205
6 2 ms 2 ms 2 ms 124.205.98.253
7 2 ms 6 MS 1 ms 202.99.1.125
8 5 ms 6 ms 5 ms 118.186.0.113
9 207 MS * * 118.186.0.106
8 ms 6 ms 124.238.226.201
One 6 ms 7 ms 6 ms 219.148.19.177
Ms Ms 219.148.18.117
Ms Ms 219.148.19.125
Ms Ms 202.97.80.113
* * * Request timed out.
Ms Ms Bj141-147-82.bjtelecom.net [219.141.147.82]
Ms Ms 202.97.48.2
* * * Request timed out.
MS-MS 221.187.224.85
Ms Ms 221.187.104.2
* * * Request timed out.
Ms Ms Ms 221.187.111.30
Trace complete.