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This article mainly shows you "the usage of DHCP protocol in Linux", which is easy to understand and clear. I hope it can help you solve your doubts. Let me lead you to study and learn this article "the usage of DHCP protocol in Linux".

I especially like the prompts on the screen when Linux starts. It tells us everything the system is doing, unlike Windows, which gives us a progress bar after the self-test, and doesn't let us know what's going on behind it.

Part of the implementation of the DHCP protocol is as follows

①: the DHCP server passively opens UDP port 67 and waits for a message from the client.

②: the DHCP customer sends a DHCP discovery message from UDP port 68.

③: all DHCP servers that receive DHCP discovery messages send DHCP provisioning messages, so DHCP clients may receive multiple DHCP provisioning messages.

④: the DHCP client selects one of several DHCP servers and sends a DHCP request message to the selected DHCP server.

⑤: the selected DHCP server sends an acknowledgement message DHCPACK, enters the bound state, and can start using the resulting temporary IP address.

No matter what we say in writing, we will find it a bit obscure, although the explanation is actually very clear.

However, when I started linux a few days ago, I noticed this small detail. During the linux startup process, I output this step step by step on the screen. I think it can make us see it more intuitively, so I took a screenshot.

As shown below:

In this diagram, what I said from step 2 to step 5 is very clear (the first step is on the server side, we can't see it), port, MAC, status are clearly marked.

DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 4 / / step 2, send DHCP discovery message

DHCPOFFER from 192.68.116.254 / / step 3, receive the DHCP message

DHCPREQUEST on eth0 to 255.255.255.255 port 67 / / step 4, send the DHCP request message

DHCPACK from 192.168.116.254 / / step 5, receive the DHCP confirmation message DHCPACK

Bound to 192.168.116.128-renewal in 826 seconds / / has been bound. 826 seconds should be 0.5T, that is, half of the IP lease. Send a request to update the lease again when the time comes.

Done.

Linux is such a good thing.

The above is all the contents of this article entitled "the use of DHCP Protocol in Linux". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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