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Questions tagged [tcp]

TCP stands for Transmission Control Protocol and is one of the core protocols of the Internet Protocol Suite. TCP complements the Internet Protocol (IP), and therefore the entire suite is commonly referred to as TCP/IP.

TCP is just one communications protocol on the web. Others include:

  • User Datagram Protocol (UDP)
  • Internet Control Message Protocol (ICMP)
  • Hypertext Transfer Protocol (HTTP)
  • Post Office Protocol (POP3)
  • File Transfer Protocol (FTP)
  • Internet Message Access Protocol (IMAP)

TCP on Wikipedia

884 questions
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Must TCP use IP?

Is it true that TCP is short for TCP/IP and they mean the same thing? Is it possible for TCP to be built on top of another protocol besides IP?
Pacerier
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How does Router know where to forward packet

If several computers with local addresses (192.168.0.#) are connected to a router and each computer opens a web browser and requests a page over HTTP, when these TCP:80 packets are sent out, the router switches the local address with the static IP…
Kornelije Petak
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What does "On-link" mean on the result of "route print" command?

I'm using Windows 7. When I type "route print" under command prompt, I get a IPv4 Route Table with several "On-link" values under the Gateway column. For example, like this one: IPv4 Route…
Junfeng
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How do I kill a process that is dead but listening?

I'm developing an app that listens on port 3000. Apparently there's an instance of it still listening to the port because whenever I start it, it can't create a listener (C#, TcpListener, but that's irrelevant) because the port is already…
Srekel
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What does SSH use UDP for?

Wile doing research I noticed that SSH both uses TCP and UDP. I completely understand the use of TCP, but UDP seems a bit strange. Why would I use an "unreliable" transport protocol with minimal handshaking for secure shell access? The only use I…
alex
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What happens to TCP connections when I remove the ethernet cable?

For a TCP connection, when I remove the cable and reconnect after 30-40 seconds there is no packet loss issues. But when the reconnect time is more than a few minutes all the packets are lost. I know it works with the retransmission timer running…
Input J
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Why is it bad to have open ports?

Here's something that has always baffled me. Why is it bad to have open ports on your computer? Assuming you don't have a virus on your computer or some other program listening to a port that may actually do something why does it matter if a port is…
aireq
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How can I see 127.0.0.1 traffic on Windows using Wireshark?

Every time I try to filter to just show a specific IP address, I get an error indicating that it is "not an interface or a field." I have no idea what that means. Furthermore, I don’t really see any localhost traffic in the logs anyway. How can I…
glutz
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How are source ports determined and how can I force it to use a specific port

When I connect to https://www.google.co.uk this changes to 216.58.198.228:443. Then a connection to me opens on [My IP Address]:63998. My question is how is 63998 port choosen and is there a way of forcing it to be 63999.
TheGathron
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How do IP answer packets reach their destination inside of a private LAN?

This is a little theory question that has been confusing me for a pretty long time. Basically, if we are inside of a private LAN, and we want incoming packets to reach, for example, an HTTP server located on one of the machines, we forward ports so…
InsomniaArray
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Do browsers create new TCP connections for each HTTP requests?

So I know that HTTP is basically just a text protocol over TCP, and that TCP is state / connection based. That means that the browser has to connect over TCP to a server before doing an HTTP request. Question then: do browsers typically create a new…
Xeon06
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Ethernet vs TCP vs IP?

What is the difference between Ethernet, TCP, and IP in simple (simple abstract) terms? Please do not copy from Wikipedia...
waka
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how to access windows localhost from wsl2?

I have windows 11 with wsl2(ubuntu) installed on it. I've setup a gdb listener server on my windows localhost and want to access it from wsl2. but it seems my windows machine and wsl vm are using different network adapters. >ipconfig Windows IP…
Mahyar Shokraeian
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How does HTTP become stateless?

HTTP is said to be stateless. Meaning, it doesn’t need to store information for the transmission of data. But HTTP uses TCP, which is state oriented. If that's the case, how does HTTP becomes stateless?
Ant's
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what is TCP Half Open Connection and TCP half closed connection

I am trying to understand what is the difference between TCP Half Open Connection and TCP Half closed connection can any one tell what exactly are they?
Registered User
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