TCP/IP status change diagram and TCP three-way handshake and four-way handshake (1)
TCP/IP status change diagram:
Detailed descriptions of each status:
CLOSED: indicates the initial state. It is the same for both the server and the C client.
LISTEN: indicates the listening status. The server calls the listen function to start the accept connection.
SYN_SENT: indicates that the client has sent the SYN pack
TCP three-way handshake1. When a connection is established, the client sends a SYN packet to the server and generates an sequential number seq number = K, waiting for the server to confirm.2. After the server receives a request, confirm the online information, send the confirmation code ACK = k + 1, Syn packet to the client, and generate an sequence number seq number = Q.3. Check whether the Ack is correct after the client receives the confirmation information. If yes, send the confirmation code
The reasons are explained in the computer network (Shehiren translation):
1. Two handshake, then if the client to the server-initiated package A1 if the fault in the transmission link, resulting in the transfer to the server time is rather lag, in this time period because the client did not receive the server for the package A1 confirmation, then will retransmit a packet A2, Assume that the server received the A2 package normally, and then return to c
client side of the process is experiencing the following status:
The server side is experiencing the following process:
"Note" in the time_wait state, if the last ACK sent by the TCP client is lost, it will be re-sent. The time required in the TIME_WAIT state is dependent on the implementation method. Typical values are 30 seconds, 1 minutes, and 2 minutes. The connection is formally closed after waiting, and all resources (including the port number) are released.
"Question 1" Why is the
When learning the network basics, the transport layer protocols include TCP and UDP;
In Linux network programming, we use the socket API to implement network communication.
So:
How does the status of Socket API correspond to that of TCP? We can see through:
How to complete three handshakes and four waves in Socket System calls:
Sock_dgram, that is, the connect operation knowledge in UDP registers the IP address and port information of the other machine in the kernel, and does not establish a l
Tags: blank application target security data packet TLS: Transport Layer Security, Transport Layer Security Protocol MTLS: mutual transport layer Securit, mutual Transport Layer Security Protocol In the OSI Layer-7 model, the network layer forwards data packets through data packet routing. As the upper layer of the network layer, the transmission layer must ensure the integrity of data transmission and data security.
able to withstand all the unthinkable attacks, which makes the SSL/TLS protocol extremely complex.Two. Basic Operating ProceduresThe basic idea of the SSL/TLS protocol is to use public key cryptography, that is, the client requests the public key to the server, then encrypts the information with the public key, and the server receives the ciphertext and decrypts it with its private key.However, there are t
, security maven and key author of Go's "crypto" codebase.
RUN the tool
Be prepared-failing grades, like the "C" below
Pay attention to the security warnings shown in color-coded message boxes. Work to fix them next.
FIX the security issues
The first significant misconfiguration reported by the above scan is the possibility of a POODLE attack. While Go doesn ' t support the older SSLV3 @ all, you can still make the server does a smarter TLS
A prefaceThe first thing to clarify is the confusion of names:1 SSL (Secure Socket Layer) is a secure transport protocol designed primarily for the web by Netscape Corporation. This kind of protocol has been widely used on the web.The 2 IETF (www.ietf.org) standardizes SSL, RFC2246, which is called TLS (Transport Layer Security), and technically, the difference between TLS1.0 and SSL3.0 is very small. Since this article does not deal with the small di
Windows TLS (thread local storage)I. TLS description and classificationWe know that in a process, all threads are sharing the same address space. So, if a variable is global or static, then all threads are accessing the same part, and if one thread modifies it, it affects all other threads. However, we may not want this, so it is more recommended to use a stack-based automatic variable or function parameter
1 Introduction to TLS technologyThread Local Storage (TLS) is a mechanism that Windows provides to address the simultaneous access of multiple threads in a process to global variables. TLS can simply be done by the operating system on its behalf to complete the mutex process, or the user can write their own function of controlling the semaphore. When a thread in
certificate. 6 and Figure 7 are shown.3, set Wireshark and fiddler to associate, New in Preferences->protocols->ssl, 8 Figure 8Figure 9The Mypem.txt file is the private key given by fiddler, the specific steps is to make a 1, 2 steps after you set up, use the phone to access the app, the Fiddler log page will automatically generate the private key (this is the first step to install plug-in role), The private key marked in the Red Line section of Figure 9 is stored in a text file, but in the fol
that HTTP does use TCP to establish a connection. If the connection is HTTPS or HTTP/2, the fourth packet will be the SSL/TLS message.
Here's a step-by-step analysis of three handshake processes:
Overview:
First handshake: Host a send bit code for syn=1, randomly generated SEQ number=1234567 packets to the server, Host B by Syn=1 know, a required to establi
OpenSSL SSL/tls mitm Vulnerability (CVE-2014-0224)
Release date:Updated on: 2014-06-06
Affected Systems:OpenSSL Project OpenSSL OpenSSL Project OpenSSL OpenSSL Project OpenSSL Description:--------------------------------------------------------------------------------Bugtraq id: 67899CVE (CAN) ID: CVE-2014-0224OpenSSL is an open-source SSL implementation that implements high-strength encryption for network communication. It is widely used in various n
certificate.
serverhellodone: a Marker message (of length zero) which says, the server is finished, and T He client should now talk.
The client must then respond with:
Certificate: The client Certificate, if the server requested one. There is subtle variations between versions (with SSLV3, the client must omit this message if it does does have a certific Ate With TLS 1.0+, in the same situation, it must send a Certificate messa
This is a creation in
Article, where the information may have evolved or changed.
The Transport Layer Security Protocol (TRANSPORT layer safety, abbreviation: TLS), and its predecessor, Secure Sockets Layer (secure Sockets layer, abbreviation: SSL) is a security protocol designed to provide security and data integrity assurance for Internet communications.
SSL contains the record layer and the transport layer, and the recording layer protocol determin
SSL (secure Sockets layer), and its successor, TLS (Transport layer Security, Transport layer safety) is a security protocol that provides security and data integrity for network communications. TLS encrypts the network connection with SSL at the transport layer. Developed for Netscape to secure data transmission over the Internet, the use of encryption (encryption) technology ensures that data is not inter
SSL (secure Sockets layer), and its successor, TLS (Transport layer Security, Transport layer safety) is a security protocol that provides security and data integrity for network communications. TLS encrypts the network connection with SSL at the transport layer.Developed for Netscape to secure data transmission over the Internet, the use of encryption (encryption) technology ensures that data is not interc
Abstract: sowhat daniel today introduced a foreign new attack mode http://www.bkjia.com/Article/200911/42521.html For TLS/SSL3.0
, It seems that there are not many people concerned, so I took a special look at the PDF.
This attack is very clever. It mainly uses TLS/SSL 3.0 to reset the encryption algorithm mechanism and the key and value structure of the HTTP request header, multiple Data combinations are i
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