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.

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TCP/IP to Serial - Serial Server

I have a server with 8 COM ports which I would like to make accessible via TCP ports, I've done quite a bit of research and tried numerous solutions including ser2net etc. All of which unfortunately ...
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181 views

Port forwarding and C++ Winsock Client-Server applications

As the title says, I'm creating a TCP client and a server program in C++. My question is, when running the client and server on two separate machines that go through a different firewalled router over ...
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95 views

TCP Client and Server Port forwarding

I have a TCP client and server program that I made. My question is, when running the client and server on two separate machines that go through a different firewalled router over the internet, does it ...
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1answer
114 views

A tool for sending and receiving plain text via TCP? [closed]

For debugging purposes, I'm looking for a tool that can do the following: Connect to a TCP socket send plain text commands receive plain text answers Yes, of course telnet can do that. But my ...
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458 views

Disable TCP keepalive on RHEL6

Is it possible to disable TCP keepalive on RHEL6? I know the kernel parameters for tuning TCP keepalive timeout are as follows: net.ipv4.tcp_keepalive_time net.ipv4.tcp_keepalive_intvl ...
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1answer
51 views

What impacts does RTT have on the behaviour of TCP?

How does round-trip time impact a TCP connection's behaviour? I know that the throughput of a connection with a high RTT is lower than the throughput of a connection with a low RTT but how does RTT ...
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1answer
269 views

Is there a software that allows RS232 sniffing and TCP/UDP listening [closed]

I am looking for a software that would fulfill the following requirements: Able to "sniff" communication over RS232 (like PortMon and Advanced Serial Data Logger) Able to listen to a given ...
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0answers
193 views

Connection Oriented Transport Protocol

Does anyone have an idea about a software for Linux that uses COTP (ISO 8073) protocol ? note : software that runs COTP over TCP , doesn't matter what is the functionality of the software i just need ...
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1answer
85 views

Create local TCP connection from C program in Ubuntu VM to Labview in Windows (Host)

Sorry if this is lengthy, I'll try to keep it as concise as possible. I have made a C program which runs in Ubuntu in a virtual machine and a Labview program running in windows (the host of the VM) ...
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0answers
16 views

Using DJB's tcpclient or tcpcat bidirectionally

Can someone post an example on how to use DJB's tcpclient bidirectionally? We need to read from Tor's ControlPort as well as write to Tor's ControlPort. A "file" that is open for both, reading and ...
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1answer
191 views

What changes to my network settings in Windows 7 can I make to achieve lower latency for gaming?

What changes to my network settings in Windows 7 can I make to achieve lower latency for gaming? I have heard of changing TCP settings in the registry, but I have also heard conflicting information on ...
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1answer
154 views

Can't capture inbound/outbound messages in Fiddler

.NET interferes with localhost traffic (there's already a lot of threads open on that topic), but something else is mangling my ability to see traffic to/from my server. I know this because I am ...
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60 views

TCP 'ip route change' not working to change cwnd on Linux

I'm trying to change the cwnd using 'ip route change'. The command I'm using: ip route change 172.16.231.0/24 dev eth0 proto kernel scope link src 172.16.231.26 cwnd lock 7. The first time I run ...
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1answer
110 views

Reverse SSH Tunneling Question [closed]

I'm somewhat confused on reverse SSH tunneling and I'd really like someone to help me out. My Goal: I'd like to create a physical backdoor to a network using a BeagleBone Black (or RaspberryPi or ...
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209 views

not all packets forwarded by pptp VPN server

I have the following setup: +------+ +---------+ ppp0---------+ |router| | A +-----+---+-----+ B | | R | ...
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1answer
381 views

virtualbox: no TCP traceroute

I have VirtualBox running Ubuntu on an Ubuntu host. The networking mode I set is NAT. I noticed that TCP traceroute-like messages (i.e. with low IP TTL) never receive any ICMP reply. Is there some ...
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2answers
157 views

Is the Transport Layer (e.g. UDP, TCP) handled by the Operating System usually? [closed]

I'm really new to networking and am struggling to understand this. I know the Transport Layer in the Internet Protocol Suite (at least the UDP and TCP protocols) contains the source and destination ...
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2answers
256 views

How do I delay tcp traffic on a socket?

I would like to test the interactions between a client program and a server program for race conditions. They connect to each other via tcp. The client does blocking calls to the server on multiple ...
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1answer
37 views

Program running from a folder where a parent folder is not accessible wont be able to use tcp layer

This issue is one that has taken me and our IT department at our company many hours to pinpoint. The problem only appears on Windows server 2008, windows 7 and windows 8. On Windows XP or Windows ...
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0answers
649 views

Linux message: Possible SYN flooding on port 25. Sending cookies

I have a Linux CentOS server online. At my console this message appeared: possible possible SYN flooding on port 25. Sending cookies. See SYN flood and SYN cookies. I have done an Apache JMeter ...
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1answer
3k views

Network issues, resolving host

My network connection randomly drops for a 5 minutes or so when I'm online. It always happens when I boot up my computer. I can tell because it says:resolving host in Chrome and I can't ping any ...
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1answer
514 views

Utility to monitor a TCP connection for drops

I found some similar questions, but not quite like this, so am going ahead and posting. I use a replication product at a client site. We are running a Windows 2003/2008 server environment. It is ...
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1answer
730 views

How to set permament TCP Windows Size in Windows XP

I'm checking real throughput of my network using iperf/jperf. Test with speedtest.net shows 25/10 - but jperf shows only 5. So I change in jperf the TCP Window Size into 256K - and now jperf shows ...
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1answer
60 views

How can my server announce its presence to everyone in the network [closed]

The situation is as follows. I want to have an application running on a server. All of the desktops in the company has to connect to it. But I do not want the IP address of the server to be hard coded ...
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1answer
820 views

How to listen to all ports (udp and tcp) or make them all appear open in Debian

I got an external Debian server. The problem is that my university campus doesn't allow connections to go outside when the port is different than TCP port 22, 80, 443, or UDP port 123. I tested them ...
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30 views

No response to ping of specific size

ping <anything> -s 473 does not receive a single reply. ping <anything> -s 476 works, as well as ping <anything> -s 472 but no size inbetween. What could be the reasons for ...
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1answer
60 views

Redirect ip to another page

i have a modem Dlink DSL-2730U i want to make this modem redirect some ip to another page or to another ip example : i have this ip : 123.456.7.9 i want to redirect it to 8.8.8.8 from ...
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1answer
747 views

Need Help Troubleshooting Network Issue (Client TCP Connections Stuck in FIN_WAIT_2)

(Note: I originally asked this question on the "Network Engineering" side, but a moderator there rejected it as "off topic" and told me to ask here instead.) I am running a video surveillance server ...
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5answers
27k views

Inbound TCP connection limit in Windows 7

I've done a bit of searching on the internet trying to find out whether there is an INBOUND TCP connection limit on Windows 7. We're writing a server product which processes data from a number of ...
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2answers
218 views

Is there a simple audio player that can be remote controlled with UDP or TCP commands? [closed]

Is there a simple audio player that can be remote controlled with UDP or TCP commands? The control needed is very simple: Stop Play Pause Volume up Volume down Next Track Previous Track
2
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1answer
619 views

TCP vs UDP. Sending data on a closed port

I try to understand differences between TCP and UDP packet on the error-checking. I know that UDP packets are connectionless and doesn't care that the packet will arrive the destination safely. And ...
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1answer
787 views

Websocket handshake response not forwarded from TCP to client

I am trying to create a websocket server. I can see the websocket client's opening handhshake. My response to it is received by the client laptop (I can see this on wireshark). So the TCP connection ...
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93 views

Is it possible to edit TCP and UDP packets?

Is it possible to edit the UDP and TCP packets a program sends? For example, we have a program that sends some information to its server. But we don't want to send some information that might be ...
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1answer
325 views

Problems with network after using a socks proxy

I was playing around with SSH and trying to route traffic through my laptop. In the end I succeeeded, however I seem to have messed up my network. I only used ssh and played around with both -D and -L ...
2
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1answer
5k views

How to send data to tcp server from command prompt [closed]

I am a java developer and quite aware of socket programming in java.I have a tcp server running my localmachine.I can write java codes for client and check communication between server and client.But ...
3
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1answer
4k views

Benchmark maximum number of TCP connections on Windows Server 2012

I am wrestling with deploying an application on Windows Server 2012. The problem is that after accepting about ~2000 TCP connections it fails to accept more. And I need much more. We have 8 cores, 16 ...
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2answers
3k views

Why are some tcp packets with the RST flag classified as new incoming connection?

While looking through my iptables log, I keep observing periodically incoming connections with the RESET flag being set from a few ip addresses within my ISP's network. This is a sample tcpdump on one ...
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2answers
1k views

eMule not connected

I'm using eMule v0.50a on Windows 7. After installation, I clicked 'connect' It is not connected. Please see the attached screenshot. It reads 'eD2K:Connecting, Kad:Connecting | Preparing' How can I ...
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2answers
572 views

Host local USB printer via port 9100 TCP

Is there a way to share a printer plugged into a PC running Windows 8.1 via USB over TCP port 9100? I have a piece of software here that only prints to such network printers and is not capable of ...
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0answers
194 views

Ethernet port on Linux machine not recognizing ethernet connection with embedded device

I have an atmel at91sam7x256 microcontroller that I would like to use for a TCP/IP communication. The very first step of my project is to be able to "ping" my board given its IP address. I have its IP ...
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1answer
40 views

Ethernet port re-transmission frequently

We have a laptop that uses its Ethernet port to connect to a device-local network, and wireless for Internet. Recently we installed Wireshark to diagnose some network problem. We found a lot of TCP ...
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2answers
3k views

What is the “-nolisten tcp” parameter for X

I have just found that my latest kubuntu comes preconfigured with the following: in directory /etc/X11/xinit there is xserverrc #!/bin/sh exec /usr/bin/X -nolisten tcp "$@" But the -nolisten tcp ...
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0answers
53 views

Hiding port number from address.

I have centos 6.5 running some web apps. Currently due the following port forwarding rules, I am only able to access my public content using 127.0.0.1:8080/ Is there anyone to just use 127.0.0.1 ...
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1answer
213 views

How are ports and URI schemes handled by a tcp/ip server?

I am working with the lwip tcp/ip stack on an embedded device, and I'm trying to understand how it all works. I've been looking through the documentation and code, but I'm confused by how ports and ...
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1answer
127 views

How can I turn on ECN for Mac OSX?

I'd like to run some networking tests with Mac OSX 10.8 and using the ECN option. However I cannot find any documentation on how to configure it. Does anybody know how to alter Mac OSX TCP networking ...
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2answers
70 views

No Internet access when second dial-up connection in Windows 7

I have a dial-up connection set apart from my normal internet access. When I connect to that dial-up , I loose Internet access (from the 1st network). When the dial-up is not active, Internet works ...
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1answer
348 views

How can I detect long-lived connections and mark them for shaping

I would like to detect TCP connections which have been open for more than one minute (or for greater than N bytes, or M packets), so I can classify them as bulk traffic ("downloads") and de-prioritise ...
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1answer
197 views

Why HTTP response is split in 2 parts: header and body?

I'm trying to understand why a single HTTP response is split in 2 parts in the following setup: Requested resource is protected by HTTP Digest Authentication on server side. Communication is ...
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4answers
1k views

Difference between the reliable delivery by link protocols and by TCP

There is a quote I forgot from which network book I copied long time ago. Some link-layer protocols provide reliable delivery on a link basis, i.e., from transmitting node, over one link, to ...
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1answer
80 views

How to add code into the linux kernel?

I am studying how to analyse and evaluate the TCP/IP protocol stack of Linux. My goal is to study the performance of the tcp/ip protocol stack as a whole, to study the time cost of each layer and ...