NTP请求报文 [英] NTP Request Packet

问题描述

我正在尝试找出需要在NTP请求程序包中发送(客户端)以从服务器检索NTP程序包的内容.我正在使用Cortex M3，Stellaris LM3S6965上的LWIP

我知道我将收到一个UDP标头，然后接收具有不同时间戳的NTP协议，以消除延迟.我可能需要制作UDP标头，但是我需要添加什么作为数据?

wireshark图片:

我希望你们能帮助我.

解决方案

客户端请求数据包与服务器回复数据包相同-只需将第一个单词中的MODE位设置为3(客户端)即可.

将整个48个字节的数据包发送到服务器，它将以相同的方式答复.

最简单的数据包将是0x1B，后跟47个零. (版本= 3，模式= 3)

I'm trying to figure out what I need to send (client) in the NTP request package to retrieve a NTP package from the server. I'm working with the LWIP on Cortex M3, Stellaris LM3S6965

I understand that I will recieve a UDP header and then the NTP protocol with the different timestamps the remove the latency. I probable need to make an UDP header but what do I need to add as data?

wireshark image:

I hope you guys can help me.

解决方案

The client request packet is the same as the server reply packet - just set the MODE bits in the first word to 3 (Client) to be sure.

Send the whole 48 byte packet to the server, it will reply with the same.

The simplest packet would be 0x1B followed by 47 zeroes. (Version = 3, mode = 3)

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