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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Assessing Performance in Process Explorer: Varying Block Sizes

I am trying to assess the performance of my scientific software using Process Explorer, with the files both locally on our blade server (Dell VRTx, Windows Server 2012) and over the network from ...
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77 views

Accessing two devices with the same IP?

I want to connect my laptop to two WiFi enabled digital cameras, that have the same IP hardcoded: 192.168.1.1 One solution that I've successfully tried: Connect one device to the laptop's built in ...
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32 views

Cannot connect to 192.168.1.1

I have router TP Link n900 and I cannot connect to my admin panel of the router, I just bought it, I have internet when I am connected with cabel, but cannot open the router. My connection is : PC -> ...
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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 ...
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24 views

Network tcp parameters

i have a netstat -s output which i would like some opinions on. Which are the parameters that seems to appear to have problems? from what I can see, tcpInUnorderBytes and tcpInUnorderSegs have some ...
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32 views

Keep alive, ESTABLISHED and TIME_WAIT semantics

When I use the following command netstat -ant | grep :9111 | awk '{print $6}' | sort | uniq -c | sort -n I get the following 1 LAST_ACK 1 LISTEN 2 SYN_RECV 7 FIN_WAIT1 51 ESTABLISHED ...
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trying knock a server using windows xp without admin access

Is there any way that i can send a single tcp syn packet to a server, iam using windows xp and cannot install any software, so it must be portable, because i have no admin access. I tried iperf, ...
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76 views

TCP connection assistance

I have 2 PCs at home connected to a router. I am trying to establish a TCP connection from PC2 to PC1. I have installed TCP Test Tool 3.0 on both and have set PC1 to listen on port 54100. On PC2 I ...
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59 views

Does an open TCP socket connection consume data when not used?

I have a TCP socket connection established between my server and a modem which has a active GSM module and sim card installed. I create this wirless 3G connection via socat: /usr/bin/socat ...
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29 views

What's wrong with this tcpdump syntax?

sudo tcpdump -i ath1 -s 0 -nne "(type mgt and subtype beacon)" Can anyone help me? I was following a tutorial at http://wiki.secarmour.com/2013/09/capture-wireless-traffic.html but seems I got ...
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46 views

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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2answers
32 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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75 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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1answer
56 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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56 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
41 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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35 views

netsh set autotuninglevel: “the parameter is incorrect”

When trying to do netsh int tcp set global autotuninglevel=disabled from a command prompt, I get the error message "The parameter is incorrect". Several search results suggested "disabling 64-bit ...
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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
51 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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14 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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66 views

not all packets forwarded by pptp VPN server

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

Reverse SSH Tunneling Question

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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1answer
77 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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51 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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53 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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63 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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21 views

SFTP upload and download speed difference

I have two Solaris box, I am using SFTP to transfer file of 1063 MB. when I do fire get (get file from server) speed is approx. 270KB/s when I do fire put (put file on server) speed is approx. ...
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535 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
65 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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32 views

How do i control a epson projector using putty

Currently i have been messing with a Epson emp 7900, trying to get it to be controlled by a python script. I have currently got a problem where if i send "PWR OFF" it will return "ESC/VP.net@" ...
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1answer
37 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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40 views

Multipath tcp application-level performance measurement

I am working on a project related to Multipath tcp and I want to measure the goodput and the RTT at the application level. I don't want to use a traditional tool(netperf, iperf, ...) and I want to ...
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27 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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41 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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iptables error “FIX ME! implement getprotobyname() bionic/libc/bionic/stubs.c”

When I do this rule, the error shows up iptables -A INPUT -p tcp -m tcp -m multiport ! --dports 80,443 -j DROP I've also found some solutions. getprotobyname() just converts protocol names like tcp ...
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45 views

Inconsistent connection to Websocket on embedded device

I am trying to set up a basic Websocket echo server on an embedded device. I'm testing the server through a very basic webpage, which simply connects upon load and sends a short message ("test") and ...
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1answer
158 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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2answers
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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
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325 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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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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Tons of connections to TCP 135 on another host on the LAN

I am facing a scenario where one server has tons of established connections to port 135 on the DB server on the same subnet. So when I do netstat -nap tcp, I got pages of pages followings, random ...
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1answer
222 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
127 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 ...
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1answer
1k 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 ...
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1answer
707 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
811 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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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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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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33 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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230 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 ...