路由跟踪路由_（_ route tracking）

跟踪路由_ _route tracking

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Tracking route Encyclopedia

The trace route Tracert (trace routing) is the routing trace utility used to determine the path taken by the IP datagram access target. The Tracert command uses the IP lifetime (TTL)Field and ICMP error messages to determine routing from a host to other hosts on the network.

Catalog

Tracert working principle

Tracert command

Solving problems with tracert

Tracert command line options

Note 1, routing detection based on record routing options

2 、 routing detection based on UDP protocol

3, routing detection based on ICMP Echo Request

4, Dos command Tracert tracking routing detailed

Other Tracert work principle

Tracert command

Solving problems with tracert

Tracert command line options

Note 1, routing detection based on record routing options

2 、 routing detection based on UDP protocol

3, routing detection based on ICMP Echo Request

4, Dos command Tracert tracking routing detailed

Other expansion edits this section Tracert working principle Respond to packets via Internet control message protocol (ICMP)that sends different IP lifetime (TTL) values to the target,Tracert

The diagnostic procedure determines the route taken to the destination. Each router on the path is requested to reduce the TTL on the packet by 1 at least until the packet is forwarded.The TTL on the packet is reduced to 0

The router should send the message "ICMP has timed out" back to the source system. The Tracert sends a response packet of TTL at 1 and increments the TTL at each subsequent sending process

1, the route is determined until the target response or TTL reaches its maximum value. Routing is determined by checking the message "ICMP has timed out" returned by an intermediate router. Some routers discard TTL directly without asking Expired packets, which are not visible in the Tracert utility.Edit this paragraph Tracert command

Print the list of the proximal router interfaces in the path of the returned ICMP timeout message in sequence. If you use the -d option, the Tracert utility does not query DNS on each IP address.

In the following example, the packet must pass through two routers (10.0.0. 1 and 192. 168.0. 1) to reach the host

172. 16.0.99. The default gateway for the host is

The IP address of the router on the 10.0.0. 1192. 168.0.0 network is 192. 168.0. 1. C:\>tracert 172. 16.0.99 -d

Trac ing, route, to, 172. 16.0.99, over, a, maximum, of, 30,hops, , 2S, 10,0.0, 1, 3S, 2S

275, MS, 83, MS, 88, MS, 192. 168.0. 1, 373, MS, 79, MS, 93, MS,Trace, 172. 16.0.99, . . .

Comp let e.

Edit this paragraph with tracert to solve the problem You can use the tracert command to determine the stop position of packets on the network. In the following example, the default gateway determines the 192. 168. 10.99

The host does not have a valid path. This may be a router configuration problem, or a 192. 168. 10.0 network does not exist (the wrong IP address) . C:\>tracert

192. 168. 10.99, Tracing, route, to, 192. 168. 10.99, over, a,maxi mum, o f, 30, hops, two

10.0.0. 1, reports:Dest ination, net, unreachable. , Trace,complete. , Tracert

Utilities are very useful for solving large network problems,where several paths can be reached at the same point.Edit the Tracert command line option in this paragraph The Tracert command supports multiple options, as shown in the following table.

Tracert [ D ] [ H maximum_hops ] [ J ] [ w主机列表

超时] t arg et_name选项描述D指定不将IP地址解析到主机名称H max i mum_ho p s。

指定跃点数以跟踪到称为t arg et_name的主机的路由-主机列表指定tracert

实用程序数据包所采用路径中的路由器接口列表。 W等待为每次回复所指定的毫秒数target_name超时超时。

目标主机的名称或IP地址。

当我们不能通过网络访问目的设备时网络管理员就需要判断是哪里出了问题问题不仅仅会出现在最终目的设备也可能出现在转发数据包的中间路由器。

有3种方式用来探测一个数据包从源点到目的地经过了哪些中转路由器这3种方式分别是基于记录路由选项的路由探测基于协议的路由探测基于UDP I CMP

的路由探测三种方式都可以用来探测一个数据包到达目的设备经过了哪些中间路由器但实现的过程却截然不同回应请求。

编辑本段注意

1、基于记录路由选项的路由探测

1、基于记录路由选项记录路由选项的路由探测

这种方式是我们最容易理解的探测路由方式。比如我想知道一封从上海发出 目的地是北京的信中间经过了多少个邮局转发。这个过程很简单只要中间邮局在转发的信件扣上他们自己的邮戳这封信到达目的地北京后北京再把这封信回邮给我当我收到回信后只要看信上的邮戳便知道中间经过哪些邮局。

平r www.aorb。 org命令便可实现这种记录中间路由的功能返回的结果是中间路由器的IP地址1。

平命令发出的是类型为8的I C MP数据报当使用平

R时这个类型为8的ICMP数据报被装在一个IP数据报里 IP数据报的选项选项字段预留出给中间路由器扣戳的地方这个地方不太大只能容纳9台中转路由器的IP地址。

2当这个数据报被发送端送出后每经过一个中转路由器 中转路由器的IP软件便会在此IP数据报的选项字段中加入一条这个中转路由器的IP地址3。

当这个数据包到达目的地时如 www.aorb。 org 目的设备便会生成一条类型为0的I CMP数据报这个I C MP数据报被封装在一个新的IP数据报里新IP数据报的选项字段中拷贝了刚才收到的IP数据报中的选项字段。

4当这个新IP数据报回送到源发送端时您便会在屏幕上看见一些中间路由器的IP地址了。

2、基于UDP协议的路由探测

Tracert是Windows下常用的命令行工具 UNIX下与之对应的是traceroute若想知道自己的电脑到www.aorb.org。

经过了多少个路由器可在命令行下输入tracert www.aorb。 org进行探测返回结果也许会与平

R相同但它是以另一种方式实现的这种方式并没有像路由记录。

选择探测技术中使用IP协议包的选项字段而是利用了IP协议包中的TTL字段。

基本思路是这样的 www.aorb。 org这台服务器即卖茄子提供HTTP 服务也卖黄瓜提供FTP服务但不卖土豆未监听的UDP端口。有位买家为了知道一封信到达蔬菜供应商www.aorb。

Org had to go through several post off ices (routers) and wrote to www.aorb.org asking about the price of potatoes.

The first step, buyers written on the envelope of the TTL positionof the number 1, when the letter reached the first post office and their adjacent, those who post the TTL value by 1,andTTL 0, the post office regulations, the TTL value is 0 letter thrown into the garbage, and then to the buyer to send a the letter called timeout letter letter letter post office name,the letter was to tell buyers who lost.

The second step, the buyer in the envelope TTL position written on the number 2, when the letter arrived at the first post office adjacent to their own, the post office of the TTL value of 1,and now TTL value of 1, the post office regulations,

The datagram with a TTL value of not 0 needs to be forwarded to the next post office, so the letter is forwarded to the next post office. When the next post office receives this letter,the post office person reduces the TTL value by 1, so TTL is 0, the post office regulations, the TTL value is 0 letter thrown into the garbage, and then to the buyer send a letter called

timeout letter letter letter post office name, the letter was to tell buyers who lost.

Through the first step, buyers know the first transit router.Through the second step, buyers know second transit routers.Then buyers only need to constantly add TTL value 1, you can according to the above steps to find out which router in the middle.

In the third step, we assume that only two post offices arrive at the destination. Then the second step, choose buyers in the TTL value is set to 3, when the letter arrived at the first post office and their adjacent, those who post the TTL value by 1,now the TTL value is 2, the post office regulations, the TTL value is not 0 packets need to continue forward to the next post.So this letter has been forwarded to a post office. Present a post officeto receivethis letter, thosewhopost theTTLvalue by 1, and TTL 1, the post office regulations, the TTL value is not 0 packets need to continue forward to the next post, so this letter has been forwarded to a post office, but under a post office is the final destination www.aorb.org, although www.aorb.orgTTLminus 1 the result is 0, but it will not discard it, because the destination is

Www.aorb.org! So www.aorb.org to deliver the IP layer of the postman delivers letters to beresponsible for selling potatoes,but we began to say, www.aorb.org does not sell potatoes, then send a called end point unreachable (ICMP type 3, code 3) letter to the buyer.

In the fourth step, when the buyer receives a letter that is

unreachable at the end of the letter, he no longer adds TTL to the letter asking for the price of the potato, because he has already known all the routes to the destination of the 1.The specific implementation process can be understood by the following two pictures

Http://lh3.ggpht.com/aorb.org/SN82f_rMiQI/AAAAAAAAAdo/eJPz7ihl1mw/s800/tracert.gif

Http://lh3.ggpht.com/aorb.org/SN82f4BcZkI/AAAAAAAAAdw/7l8A3fJy_y4/s800/tracert2.gif

3, routing detection based on ICMP Echo Request

This method of detection is similar to the implementation of routing detection based on UDP protocol, but the sender sends not a UDP packet, but sends a Echo of ICMP type 8

Request (echo request) data message. As with the UDP routing protocol based on detection technology, each sender will put the value of TTL plus 1, each transit routers on the TTL value by 1, if 0, then dropped to the sender sends a timeout message,if not 0, will continue to be forwarded to the next hop. The only difference is that when the datagram reaches the final destination node, the sender sends the Echo

Request message, so the receiver will correspond to a ICMP data message of type 0. Thus, when the sender receives a data message of type ICMP, 0, it is known that all routes have been queried and terminated to continue detection.