Linux shell编程学习笔记67： tracepath命令 追踪数据包的路由信息

0 前言

网络信息是电脑网络信息安全检查中的一块重要内容，Linux和基于Linux的操作系统，提供了很多的网络命令，今天我们研究tracepath命令。

Tracepath 在大多数 Linux 发行版中都是可用的。如果在你的系统中没有预装，请根据你的发行版使用下面的命令进行安装。

Windows中没有tracepath命令。

1 tracepath命令 的功能、格式和选项说明

1.1 tracepath命令 的功能

tracepath命令的功能是追踪数据包的路由信息，它可以追踪并显示数据包到达目的主机所经过的路由信息，以及对应的MTU值。

tracepath 与 traceroute 类似，用于确定数据包访问目的地所经历的路由路径。

Tracepath 特别适用于没有 root 权限的用户，因为它不需要特权即可运行。

1.2 tracepath命令 的格式

跟ping命令一样，我们可以使用 tracepath 或 tracepath -?命令获取ping命令的格式信息。 tracepath不支持 --?选项。

[purpleendurer @ bash ~] tracepath
Usage: tracepath [-n] [-b] [-l <len>] [-p port] <destination>
[purpleendurer @ bash ~] tracepath -?
Usage: tracepath [-n] [-b] [-l <len>] [-p port] <destination>
[purpleendurer @ bash ~] tracepath --?
tracepath: invalid option -- '-'
Usage: tracepath [-n] [-b] [-l <len>] [-p port] <destination>
[purpleendurer @ bash ~] 

 tracepath [-n] [-b] [-l <最大路径长度>] [-p 端口号] <目标域名或IP地址>

1.3 tracepath命令选项说明 

与ping命令相比，tracepath的命令不算多。

不过不同版本的Linux提供的tracepath命令选项不尽相同。 

选项	说明
-n	输出数字格式的地址
-b	输出回程路径
-l  最大路径长度	设置最大路径长度
-m 最大TTL值	设置查询的最大TTL值
-p 端口号	设置UDP端口号
-V	显示版本信息

2  tracepath命令实例

2.1 tracepath g.cn

[purpleendurer @ bash ~] tracepath g.cn1?: [LOCALHOST]                                         pmtu 15001:  26.10.178.42                                          2.037ms 1:  26.10.178.42                                          2.238ms 2:  11.73.57.238                                          1.986ms 3:  11.73.37.65                                           1.852ms 4:  11.73.49.81                                           3.004ms 5:  10.222.215.161                                        2.377ms 6:  10.54.171.129                                         3.831ms 7:  10.102.154.246                                        4.610ms asymm  6 8:  no reply9:  no reply
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30:  no replyToo many hops: pmtu 1500Resume: pmtu 1500 
[purpleendurer @ bash ~] 

命令返回信息中的PMTU  （Path Maximum Transmission Unit，数据通信网络中发现路径最大传输单元）是优化网络性能的关键技术之一。PMTU决定了数据在网络中传输的最大数据包大小 。

2.2  tracepath -b g.cn ：输出回程路径

[purpleendurer @ bash ~] tracepath -b g.cn1?: [LOCALHOST]                                         pmtu 15001:  26.10.178.42 (26.10.178.42)                           2.308ms 2:  11.73.56.206 (11.73.56.206)                           1.952ms 3:  11.73.31.193 (11.73.31.193)                           2.034ms 4:  11.73.48.73 (11.73.48.73)                             2.678ms 5:  10.222.214.217 (10.222.214.217)                      15.309ms 6:  10.54.171.141 (10.54.171.141)                         3.707ms 7:  10.102.154.222 (10.102.154.222)                       4.003ms 8:  no reply9:  no reply
10:  114.243.132.194 (114.243.132.194)                     5.394ms asymm  9 
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[purpleendurer @ bash ~] 

2.3 tracepath -l 512 g.cn：设置最大路径长度为512

[purpleendurer @ bash ~] tracepath -l 512 g.cn1:  26.10.178.42                                          2.625ms 2:  11.73.56.206                                          1.956ms 3:  11.73.37.161                                          1.943ms 4:  11.73.50.209                                          3.318ms 5:  10.222.214.241                                        3.257ms 6:  11.94.197.101                                         3.779ms asymm  7 7:  116.251.112.161                                       4.019ms asymm  6 8:  no reply9:  no reply
10:  114.243.132.194                                       5.299ms asymm  9 
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[purpleendurer @ bash ~] 

 2.4 tracepath -p 80 g.cn：使用UDP 80端口

[purpleendurer @ bash ~] tracepath -p 80 g.cn1?: [LOCALHOST]                                         pmtu 15001:  26.10.178.42                                          2.337ms 1:  26.10.178.42                                          2.357ms 2:  11.73.56.78                                           1.909ms 3:  11.73.36.129                                          1.877ms 4:  11.73.43.185                                          2.385ms 5:  10.222.214.193                                        2.221ms 6:  10.54.171.221                                         3.892ms 7:  116.251.112.157                                       3.971ms asymm  6 8:  no reply9:  125.33.184.177                                        4.492ms asymm  8 
10:  114.243.132.194                                       4.819ms asymm  9 
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[purpleendurer @ bash ~] 

2.5 tracepath -n g.cn ：输出数字格式的地址

[purpleendurer @ bash ~] tracepath -n g.cn1?: [LOCALHOST]                                         pmtu 15001:  26.10.178.42                                          2.073ms 1:  26.10.178.42                                          2.068ms 2:  11.73.57.174                                          1.826ms 3:  11.73.32.57                                           2.603ms 4:  11.73.52.81                                           2.285ms 5:  10.222.215.113                                        2.359ms 6:  10.54.171.141                                         3.860ms 7:  10.102.154.234                                        3.791ms 8:  no reply9:  no reply
10:  114.243.132.194                                       4.967ms asymm  9 
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[purpleendurer @ bash ~]