Questions tagged [tcp-ip]
377 questions
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Connecting to Informix Connection Manager Using JDBC
I need some clarification on how (some) JDBC drivers connect to (Informix) Databases.
We had the issue of 'connection refused' when trying to connect to Informix connection manager from a Java application via JDBC,although access was granted via firewall.
When we consulted Informix Team,they told us...
1
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0
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102
Views
Simple TCP/IP client not working as expected
I am attempting to write a very basic TCP/IP client that will simply request user input, send that input to the specified IP, then read the output. The code below does not return any of the error codes but the output is still not returning as expected. For example, the device I am testing this on sh...
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77
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Embedded linux TCP/IP communication issue
I have TCP/IP server running under embedded linux:
int sId = socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK, 0);
sockaddr_in servAddr;
servAddr.sin_family = AF_INET;
servAddr.sin_addr.s_addr = htonl(INADDR_ANY);
servAddr.sin_port = htons(5000);
bind(sId, (sockaddr*)(&servAddr), sizeof(servAddr));
liste...
1
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1
answer
195
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rtsp streaming from desktop-server to my client
I have a TCP server running on my desktop (used as a server). I want to use the RTSP streaming of a video from the server to the ijkmediaplayer client (display that on Android). How can I achieve that?
Have I to run an RTSP-server also for this on my desktop?
How to specify the path of the video-fil...
1
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1
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73
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Best way to execute commands to TCP/IP console from PHP
Before I start, excuse my english, I'm from Holland :)
I have a question regarding the use of PHP's fsockopen.
My Prerequisites
So basically, I have a Windows program running in the background which has a remote console over TCP/IP that I need to connect to so I can execute a few commands. I am abl...
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1
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411
Views
Connectex: Error connecting to a physical device
I am trying to communicate with a device (connected using ethernet) using TCP/IP connection. When a connection request is sent, I am getting an error:
dial tcp 192.168.137.10:502: connectex: A connection attempt failed because
the connected party did not properly respond after a period of time,
or...
1
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1
answer
156
Views
Creating application level packets in Python
I have a basic multi-threaded client server running using python 3.6
Now once a connection is established I want to create application level packets which will be sent over tcp/ip. The purpose of these will be make a three-way handshake to identify multiple clients then authenticate them. the packet...
1
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0
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88
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Telnet inner-workings: Is telnet server necessary if client connects to an HTTP server?
One way to quickly test the first-order functionality of a web server is to use the application layer tool Telnet, e.g. How to send an HTTP request using Telnet.
This is the usage I am most familiar with, but today I learned there is such a thing as a Telnet server: https://askubuntu.com/questions/6...
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736
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The requested address is not valid in its context when listen data from other machine
hello i am using tcp ip communication using c# when my code listen from IP then its give me error message the requested address is not valid in its context. here is the code.
TcpListener server = null;
try
{
// Set the TcpListener on port 13000.
Int32 port = 5555;
IPAddress localAddr = IPAddress.Par...
1
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0
answer
91
Views
transport header in sk_buff
Is it guaranteed that skb->transport_header is always correctly set on ingress path? Specifically, I'm setting a tc qdisc on interface, and attach to it filter with tc action; this path qdisc->filter->action exists before the packet hits TCP/IP stack, therefore I'm assuming that packet layers, netwo...
1
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1
answer
174
Views
Hazelcast need to be connected as client in the existing cluster instead of member
The changes which I made in server side:
@Bean(name = {'hazelcast'})
public HazelcastInstance hazelcastInstance() {
ClientConfig clientConfig = new ClientConfig();
clientConfig.getGroupConfig().setName(integrationSettings.getHazelcastClusterGroupName())
.setPassword(integrationSettings.getHazelcastC...
1
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0
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75
Views
Sending String over TCP/IP uisng C#
I have a robotic system that can be interacted with over TCP/IP. I have been able to control the system in Matlab using the following code:
AT = tcpip('cim-up',8000);
fopen(AT);
fprintf(AT, '$global[1] = 33');
I need to emulate the same command in C#. I have tried the following code:
// Connect to R...
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1
answer
17
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How to get data from a device connected in a local network to my application
I am trying to get data from a device which is connected in the local network.
The device listens to 192.168.1.2:10000
For example we can call the function getItems() on the windows computer in the network and we get all the items.
Now I want to do this in my cloud application (php). So I want th...
1
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1
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112
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Linux tcp server can't bind to a close_wait port
I tried to let tcp server bind to a close_wait port, but it caused a Errno::EADDRINUSE error.
I created a tcp server that listen on port 55555. Then client connected to that server. After some ops, run ss -at | grep 55555.
# ss -at | grep 55555
LISTEN 0 128 *:55555...
1
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1
answer
306
Views
How can iperf reporting packet loss in udp
Iperf is the well known tool to calculate throughput.
When i tried udp throughput using iperf on my linuxpc,
It reported that 10% of packet loss.
In UDP protocol, data gram did not receice any acknowledgements.
But, in what way iperf is reporting or calculating packet loss ?
How would iperf tool kno...
1
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0
answer
88
Views
psql/heroku connection refused, does not accept TCP/IP connections on port 5432
I've been trying to run heroku run python manage.py migrate on my Django app but I keep getting this error message:
psycopg2.OperationalError: could not connect to server: Connection refused
Is the server running on host 'localhost' (127.0.0.1) and accepting
TCP/IP connections on port 5432?
I have t...
1
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0
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34
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How to send a SYN packet to a web server with javascript?
So in order to try and hack into my own web server for security reasons, I would like to try and open many half-connection to dos my server. So how would I manually send an SYN packet to the server. I know that you can do this with the python library Scapy, but i would prefer to do this with javascr...
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68
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Couldn't send data to thingspeak via Sim 800
I have connected the sim800L to my PC via TTL connector. Using 'putty' I tried to send data to thingspeak through sim 800 GSM module by using following AT commands.
AT
AT+CPIN?
AT+CREG?
AT+CGATT?
AT+CIPSHUT
AT+CIPSTATUS
AT+CIPMUX=0
AT+CSTT='www'
AT+CIICR
AT+CIFSR
AT+CIPSTART='TCP','184.106.153.149',...
1
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1
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140
Views
Telnet to a port that is already in use
I'm trying to use telnet to check if the port of an application is open.
But i'm receiving the following error:
Connecting To 192.168.1.10...Could not open connection to the host, on port 3001: Connect failed
I assume the port is closed, but is it also possible the port is being in use by another...
1
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0
answer
62
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Can POSIX sockets abort a TCP 3-way handshake?
I'm working on a load balancer probe engine that sends probe requests to servers to determine their availability.
The probe configuration has a TCP-only setting where server availability is detected by setting up a TCP connection followed by a disconnect.
The disconnect can be a TCP RST (depending o...
1
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1
answer
40
Views
Does TCPdump strip any headers when receiving packets?
So i am attempting to send an already constructed packet over a RAW socket interface (these are packets that have been previously captured and i want to resend them without changing the packet integrity) and am using TCPdump to check that the packets are going over correctly (surprise they are not)....
1
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1
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3.5k
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Windows 7: Change the priority of traffic to wired instead of the wireless connection?
On Windows 7 clients I have to change the metric of the wired network connection to a lower metric than the wireless so traffic is prioritized over the wired connection. Is there a way to do this through a script using powershell?
To do this manually i -> Open network and sharing centre -> click th...
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1
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177
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Network Connection closing
Please help me decode the following. I have a problem in the network, unable to figure out where it is. Follow is the decode summary we got from the capture by running the OPNET software.
I think Connection 2 is successful, where the client ends with FIN, and connection 1 ends prematurely issuing RS...
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2
answer
116
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Howto - Authenticating a calling assembly across a tcp/ip boundary
I have an server engine, which generally works in the server (imaginatively). But occasionaly it will be executing on a client, or occasionally on another server, and will be wanting to use this server to do some of extra/additional processing.
The link between will be protected by ssl/tls and certi...
1
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1
answer
830
Views
Web server with OpenSSL
I was trying to compile my web server, but these things like below happened:
gcc -o webserv.o webserv.c -c -ansi -pedantic -Wall -lssl -lcrypto
webserv.c: In function ‘main’:
webserv.c:33: warning: ‘OPENSSL_add_all_algorithms_noconf’ is deprecated (declared at /usr/include/openssl/evp.h:828)...
1
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1
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2.3k
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How to open a TCP/IP port to a printer in VB6
I was wondering if somebody knows how to connect to a thermal printer with a TCP/IP interface using Visual Basic 6. It is to send ESC/POS command to the printer so that I can control it directly without the need to use a driver.
The problem is on the first line; how do I establish a connection with...
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1
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4.5k
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Modbus TCP/IP device communication problems
I'm trying to communicate with a device using Modbus TCP/IP. I'm using C# 4.0 .NET Sockets and have run into trouble getting responses back from the device. It will have to be asynchronous communication due to the nature of the device/network.
Right now I can connect to the device. When the Conne...
1
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1
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245
Views
recv() function do not get message back in python
I am new to TCP/IP connection using python
I have this simple code:
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(('www.google.com',80))
s.send('GET /\n')
while 1:
received = s.recv(1024)
if received:
print received
but when I run it it just runs forever and does n...
1
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1
answer
555
Views
Putting a delay when using asynchronous socket methods
I am using C#, .Net Framework 3.5 for software development. My application connects to multiple clients over TCP/IP at once and collects some data from them. The client number is very high(over 100). Before my application development process, i have done some researches and seen that i must use asyn...
1
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2
answer
655
Views
Can the Micrel KSZ8995 be coaxed into abiding by RFC 3927, so as not to leak link-local addresses?
My embedded system uses a Micrel KSZ8995M switch, connected to two 'internal' devices (and by internal I mean sitting physically on the same board) and a LAN.
Device 1 is a ARMv5 processor running Busybox Linux, with a LAN IP configured either by DHCP or statically on eth0, and a link-local/APIPA 16...
1
votes
1
answer
1.7k
Views
What is the sender IP address used for in an ARP REQUEST packet?
So in an ARP request packet, we have 'Who has 192.168.1.1? Tell 192.168.1.143'. The reply however is not 'sent' to the IP address 192.168.1.143, but to the MAC address associated with it. What is the purpose of having the sender's IP address?
Thanks.
1
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1
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881
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tcp connection from webpage to android app
Wanted to make a TCP/IP chat interface between the TCP/IP socket sporting app on my Android and similar TCP/IP implication in PHp on the webpage where my website is hosted.
I have previously formed TCP/IP app which is able to talk with my computer (where another java tcp server is loaded) but now I...
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1
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2.1k
Views
Maximum number of concurrent threads inside Windows Azure Worker Role
We are developing a server application that needs to open a lot of TCP/IP connections concurrently awaiting for some small notifications.
We are planning to use Windows Azure Cloud Services for easy scale of the server but we have only one doubt.
What is the maximum number of concurrent threads (or...
1
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1
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696
Views
Does TCP sliding / congestion window shrink if connection is idle?
If so, are there any reasonable guesses an application can make, or better yet an API call, to determine how long of idling causes the window to shrink?
Do applications that need low-latency send unnecessary traffic periodically when idle to preserve the window size?
Another way to phrase the questi...
1
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1
answer
1.4k
Views
testing user-space TCP/IP stack with TUN / TAP
Is it possible to test an TCP stack using TUN / TAP interfaces ?
I'm thinking of a mechanism like this:
+--------------------------------+
| TCP Client / Server |
| socket(AF_INET, SOCK_STREAM) |
| e.g. HTTP Server / Client |
+----------+---------------------+
|
| +---------------...
1
votes
1
answer
1.7k
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Using SSL based tcp/ip sockets in Android
I 'm trying to Secure my TCP/IP based Socket connection using SSL for Android platform.
here is some snippet from my code:
Client Side:
SSLSocketFactory sslFact = null;
SSLContext ctx;
KeyStore ks;
char[] passphrase = 'hosttest'.toCharArray();
ks = KeyStore.getInstance('BKS');
ks.load(SSLActivity....
1
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5
answer
214
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Can javascript pick up inbound links
Can a jquery or javascript pick up inbound links on a page?
For example, I need to determine whether a page was a) reloaded b) entered from a foreign link or c) clicked on by a link within my domain name
1
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1
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466
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Determining whether an TCP stream has been disconnected
I am in a situation where I need to open up a stream between my listener and a TCPClient. Once the stream is open, the client will send a stream of messages, and I will send an ACK for each. If I don't get any messages for a set amount of time (5 minutes by default), I will disconnect from the serve...
1
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2
answer
271
Views
How do I Connect my Android device remotely using TCPIP?
I am new in Android development and currently I face some issues regarding connect my Android device remotely using TCPIP, any help will be appreciated.
Thanks in advance.
1
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1
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416
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TCP IP recv() function not receiving the echoed message from server
I'm using a TCP IP socket program in Windows, in which i created a client for transmitting data to the server and the server is echoing the messages back to the client (please note the server has been verified working properly with telnet application).
But When I send a test message from client it g...