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.

learn more… | top users | synonyms

1
vote
0answers
19 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 ...
0
votes
1answer
23 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 ...
0
votes
0answers
13 views

Restarting TCP proxy connection [on hold]

Is there a way to restart a connection after calling shutdown on server in TCP proxy setup? The first transfer takes place, then I suspend it by pressing z RETURN. Then I start a new telnet session ...
1
vote
2answers
22 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 ...
0
votes
1answer
30 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 ...
1
vote
1answer
44 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 ...
0
votes
0answers
27 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 ...
0
votes
1answer
25 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) ...
0
votes
0answers
23 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 ...
2
votes
0answers
7 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 ...
0
votes
1answer
23 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 ...
0
votes
0answers
7 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 ...
0
votes
0answers
41 views

not all packets forwarded by pptp VPN server

I have the following setup: +------+ +---------+ ppp0---------+ |router| | A +-----+---+-----+ B | | R | ...
0
votes
1answer
51 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 ...
0
votes
1answer
50 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 ...
0
votes
2answers
40 views

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

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 ...
0
votes
0answers
29 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 ...
1
vote
2answers
49 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 ...
0
votes
0answers
19 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. ...
0
votes
0answers
301 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 ...
1
vote
1answer
52 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 ...
0
votes
0answers
19 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@" ...
-1
votes
1answer
33 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 ...
0
votes
0answers
37 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 ...
0
votes
0answers
25 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 ...
1
vote
1answer
37 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 ...
0
votes
0answers
60 views

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 ...
0
votes
0answers
30 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 ...
0
votes
1answer
86 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 ...
-1
votes
2answers
62 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
0
votes
1answer
182 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 ...
1
vote
0answers
42 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 ...
0
votes
0answers
16 views

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 ...
0
votes
1answer
125 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 ...
0
votes
1answer
96 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 ...
1
vote
1answer
769 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
votes
1answer
340 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 ...
0
votes
2answers
452 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 ...
-2
votes
2answers
221 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 ...
0
votes
0answers
100 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 ...
0
votes
1answer
31 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 ...
0
votes
2answers
161 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 ...
0
votes
0answers
43 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 ...
1
vote
1answer
72 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 ...
1
vote
1answer
90 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 ...
0
votes
1answer
39 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 ...
4
votes
1answer
1k views

For what does ssh use UDP?

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 ...
1
vote
1answer
96 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 ...
0
votes
1answer
49 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 ...
1
vote
0answers
156 views

Iperf tests in reverse direction

I used iperf to measure the max throughput for TCP connection between two ubuntu machines. Both the machines were directly connected be means of a 1Gbps cable. When I performed iperf tests i obtained ...