PPP protocol workflow, combined with ppp-2.4.9 source code analysis

ppp-2.4.9 source code analysis PPP agreement workflow When a user dials in to an ISP, a physical connection is established from the user's personal computer to the ISP. At this time, the user's personal computer sends a series of LCP packets (encapsulated into multiple PPP frames) to the ISP to establish the LCP connection. These packets ...

Added by fpbaum on Tue, 08 Mar 2022 16:13:27 +0200

Computer network - top-down notes - socket programming

Socket programming 🐣 Because socket programming is very huge, this paper, as a learning note, only realizes the relatively simple and basic part, but I hope it will be helpful to you Links to all computer network learning notes Sockets are different when identifying communication endpoints External: use IP address + port numberInterna ...

Added by verano on Sat, 05 Feb 2022 15:03:07 +0200

Content security policy CSP

Content security policy (CSP) is an additional security layer used to detect and weaken certain types of attacks, including cross site scripting (XSS) and packet sniffing attacks. Website maintainers use CSP to define the rules of some content sources, and then tell the browser these rules in some way. The browser determines which source ...

Added by moporho on Sun, 30 Jan 2022 13:49:38 +0200

Computer network: detailed explanation and expansion of real problems of application layer postgraduate entrance examination

I Single choice questions (11 questions in total, 100.0 points) 1[2009] FTP Transfer between client and server FTP Command, the connection used is (). A,Based on TCP Control connection above B,Based on TCP Data connection on C,Based on UDP Control connection above D,Based on UDP Data connection on Correct answer: A FTP uses TCP 2[2010]If t ...

Added by keithschm on Sat, 29 Jan 2022 14:52:28 +0200

It's almost the new year. You won't have a girlfriend (boyfriend) yet. Ba, no, no, No. then it means that you deserve to have the code~

preface Hi ~ Hello, everyone, this is the demon king! I send articles ~ usually reptiles, but what Reptiles look too much. It's bad for your health. Let's have some reality today!! It's almost the new year, and my family is urging me. I can't escape this year. Why can't I? The status quo is ba next year Learn the confession code, install ...

Added by chrys on Fri, 21 Jan 2022 08:18:44 +0200

Understand the OSI seven layer model and TCP three handshakes and four waves

Summary of key points Basic concepts bit, Byte, rate, bandwidth, throughput, delay, delay bandwidth area, round trip time, utilization, packet loss rate OSI seven layer model Physical layer, data link layer, network layer, transport layer, session layer, presentation layer and application layer OSI network standard model Physica ...

Added by HERATHEIM on Mon, 17 Jan 2022 20:32:46 +0200

ACL access control list

1, Introduction Access control list (ACL) is a list of instructions (i.e. rules) applied to the router interface. These instruction lists are used to tell the router which packets are acceptable and which packets need to be rejected. 1. Working principle ACL uses packet filtering technology to read the information in the layer 3 and laye ...

Added by yaatra on Tue, 28 Dec 2021 21:32:42 +0200

[network security] bottom layer extension and production of deserialization vulnerability WebShell

XMLDecoder deserialization vulnerability underlying The reference articles have been analyzed in great detail. Here I mainly talk about the final implementation. That is, the use of the Expression class import java.beans.Expression; public class test { public static void main(String[] args)throws Exception { Parameter();//With ...

Added by Cbrams on Tue, 28 Dec 2021 05:50:04 +0200

Write an HTTP forward proxy

concept First, let's understand the related concepts of HTTP proxy. Generally speaking, there are two types of HTTP proxy, one is forward proxy and the other is reverse proxy. Although they are all proxies, there are still differences. The VPN we usually use is the forward proxy. We specify a server, and then connect to the server through the ...

Added by ununium on Tue, 07 Dec 2021 08:06:39 +0200

Multiplexer epoll

epoll related system calls #include <sys/epoll.h> int epoll_create(int size); epoll_create creates an epoll model and returns a file descriptor pointing to the epoll model.Parameter is deprecated and reserved for compatibility. Fill in at will.The file descriptor is returned successfully, and - 1 is returned for failure. int e ...

Added by mjs87 on Sun, 05 Dec 2021 13:05:54 +0200