Questions tagged [sockets]

A communication end-point for networking, for CPUs please use [processor-socket]

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socket.error: [Errno 10013] Port forbidden access permissions

When trying to use a Python script I get this error: socket.error: [Errno 10013] An attempt was made to access a socket in a way forbidden by its access permissions I put the post on ...
user1494941's user avatar
4 votes
1 answer
894 views

What happens when I terminate a process and the socket send buffer is not empty?

In Windows (and probably in other operating systems), if a process has a TCP connection with another process on another machine, and then I terminate the process, an RST packet will be sent to the ...
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Can't connect to socket listening on 127.0.0.1 but works for 'localhost' in Windows 10

I have a clean install of Windows 10 Pro x64 and I’m trying to run PostgreSQL server on it. It used to work perfectly on Windows 7, but Windows 10 is behaving really weird: If I configure PostgreSQL ...
extesy's user avatar
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How to free a port on OS X when lsof(1) reports that it is not in use

I am a developer working in OS X on Eclipse. A bug I have been working to fix in a web application results in some very strange behavior when resetting an instance of Tomcat, resulting in the ...
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How do I troubleshoot if I see the incoming packet in tcpdump, but not at the socket?

For example, I see that the incoming packet in tcpdump, but not in strace for the program that is listening the appopriate socket. How do I trace the "fate" of this incoming packet on Linux? I ...
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Is it necessary for an RST packet to have an acknowledgement number?

I am studying about TCP reset attack. I know that some RST packets have an acknowledgement number (with the ACK bit set), and some RST packets do not have an acknowledgement number (the ...
user572563's user avatar
3 votes
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How to monitor the unix socket statistics in OSX per-seconds

I can monitor a net-device in the OSX, like below $ netstat -I eth0 -b 1 1000 input (Total) output packets errs bytes packets errs bytes colls ...
Romain Xie's user avatar
3 votes
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netstat -o timer value "probe"

A bit of background on the scenario. I have a distributed application running on RH6.5 that uses JMS (OpenMQ 4.5.2) to send messages between hosts. One host (Host A) receives information from network ...
Nuno Perpetua's user avatar
3 votes
1 answer
5k views

SYN-ACK not received

On a standard TCP connection between server and client, I have this issue: the SYN-ACK is not received from the client, while it is sent from the server. I could see this on Wireshark from both server ...
Fra H's user avatar
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Simulating a network issue for a specific application

This is somehow a developer question, but as it is more related to operating systems and network connections, I will post it here and not on Stack Overflow. I'm trying to simulate a situation when a ...
ov1d1u's user avatar
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Differences in RJ-45 plugs & keystone jacks for CAT5, CAT5e, CAT 6, CAT6a & CAT7 compliance?

I've read detailed insights on differences in the CAT Cabling. What is the difference between various cable types like Cat 5, Cat 5e and Cat 6? What is the difference between Cat 6 and Cat 6e ...
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Can apache httpd listen on a unix socket?

I would like httpd (Apache 2.4.x) to serve HTTP requests over a UNIX domain socket. The Listen directive doesn’t seem to allow for specifying sockets. Is there perhaps another (undocumented?, module?) ...
phg's user avatar
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WebSocket connections originating from local network all use same client-side port (instead of ephemeral) when connecting to local webserver - Why?

I set up a webserver on a virtual machine on my home desktop. I have my router forward several ports (80, 443, etc) to my desktop, when then forwards them via NAT to the virtual machine (see diagram ...
SAlsum's user avatar
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Multiple Processes listening on Port 22? How is this possible?

I have a Solaris 10 Server that has SSH enabled, I wanted to find out which specific process is responsible for opening the socket that listens for the port 22. I used the PFiles utility to loop over ...
EvilSapphire's user avatar
2 votes
1 answer
4k views

how to read UDP buffer size on windows 10?

I have a server application that will receive more than 200 udp packet concurrently (strings of max 64 bytes), for testing and performance purpose I want to check the UDP buffer in my server to check ...
Luigi Sorbilli's user avatar
2 votes
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285 views

How can I use the "location of socket in memory" field in /proc/net/tcp

I'm working on a proxy for linux(C++) that, amongst other functions, keeps track of tcp connections and associates them with the process's pid. To do that, I get the inode in /proc/net/tcp and then ...
Tiberiu Hodorogea's user avatar
2 votes
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993 views

Need help figuring out a random connection timeout issue on a server

I discovered this issue trying to loadtest a custom node.js websocket server, where some sockets are failing to connect (they hit the connection timeout). It does not appear to be related to the ...
amnesia's user avatar
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Why is an SSH socks5 proxy performing better than a normal socks5 proxy?

I've been trying to setup a proxy tunnel for gaming for the past month and have encountered (To me) a very strange issue. Currently I'm using a socksifier to redirect/edit the connect() command on a ...
VirtualSmile's user avatar
2 votes
1 answer
2k views

postfix connection to opendkim refused

I'm trying to send mail from my ubuntu (17.04) server to gmail, hotmail but the email is going to spam folder. I've checked /var/log/mail.log and I found out that there is a warning about opendkim ...
Nadav Shabtai's user avatar
2 votes
1 answer
837 views

What happens if all of the Ephemeral Ports are used in Windows?

If all of the Ephemeral Ports are used, and another socket tried to connect to a server, will the connection fail? or will the socket be assigned a port outside the range of the Ephemeral Ports?
user607018's user avatar
2 votes
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324 views

lsof: restrict to sockets available via loopback

I can restrict the selection to sockets listening only on the loopback interface: $ lsof -p "$(pgrep -d, proga)" [email protected] -sTCP:LISTEN -P -n -a COMMAND PID USER FD TYPE DEVICE SIZE/OFF ...
user19087's user avatar
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"Could not create unix socket lock file" with MySQL 5.7.10 on OS X 10.11.2

I've been trying to install MySQL 5.7 on OS X El Capitan using Homebrew, however when it came to getting the server up and running, I cannot seem to get a lock file created. When I run mysqld_safe, ...
Mark's user avatar
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VirtualBox and Websockets

I am using Virtualbox with Linux host and Windows guest. When I try to use websites that makes use of websockets it's not working properly (not getting messages). I believe this can be fixed with ...
Martynas's user avatar
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1 answer
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How to Maintain an Inactive Tcp Connection?

If a TCP server establishes a TCP connection with a TCP client and the TCP client never sends any packet to the server. I roughly know firewalls near the TCP server may send an RST to it. Or there is ...
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How does the Inetutils telnet utility determine if a connection is still alive?

I've started using sockets in programming with Java (I have experience with Python), and while testing a server that I'd written with the telnet command, I noticed that the utility responds ...
Michael Smith's user avatar
2 votes
1 answer
3k views

Tunnel a ssh tunnel through a unix socket and connect to it using ssh

Ok, the title might be a bit confusing so here's what I'm trying to achieve. I have multiple machines of types A that would connect to a server B. All machines of type A would have some kind of GUID. ...
Loïc Faure-Lacroix's user avatar
1 vote
0 answers
50 views

Why does FileZilla start its own ssh-agent process?

Why does FileZilla start its own ssh-agent process? When I open my terminal, an ssh-agent gets created with socket location /var/folders/sm/4bt9kz951dg4s5kq1jwy57tc0000gn/T//ssh-nWola5Puaw6o/agent....
kataba's user avatar
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1 answer
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Cannot run recent versions of Node.js in Vagrant box anymore

I like to do my dev work in Vagrant virtual machines to keep a clean environment. Having recently updated Node.js to v18.18.0, I suddenly cannot run npm commands inside the guest any longer: npm start:...
BadIdeaException's user avatar
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185 views

Is there a way to close down a port used by a service during shutdown or boot?

I have some service listen.service which makes the machine act as a TCP server which other clients can connect to. The problem is once the service starts up, it doesn't actually do anything for about ...
frend123123's user avatar
1 vote
0 answers
39 views

TCP server device for USB access readers

I have a BarCode reader that spits out data over a Virtual COM port (RS232 Serial) through a USB cable. I have a server running and managing a facility, and I need to read data coming off the BarCode ...
Aman's user avatar
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1 vote
0 answers
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Bash: read from socket file descriptor returns always the same data instead of blocking

I have a postgres started like this: exec 3< <(su -l postgres -c "/usr/local/pgsql/bin/postmaster -p '$port' -d 3 -D '$backupDir' 2>&1 & echo \$!") This redirects all logs ...
Torge's user avatar
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1 vote
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865 views

systemd StandardOutput redirection does not work with a systemd socket

I have a systemd service like this (my-server.service): [Unit] Description=My Server After=syslog.target network-online.target my-server.socket [Service] Type=simple ExecStart=/usr/bin/java myserver....
jangxx's user avatar
  • 111
1 vote
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44 views

understand ss -to4 output for a jdbc connection

My application connects to a database over JDBC, and performs a lot of sequential inserts. There is only 1 JDBC connection opened by the application. As the performance is not as expected, I started ...
iGnite007's user avatar
1 vote
0 answers
3k views

failed: Error during WebSocket handshake: Unexpected response code: 400

I am using apache2 AWS server to deploy my project. My project is developed using NodeJS and ReactJS. For the last few days sever responds with this error, WebSocket connection to 'wss://staging....
sanil sathyan's user avatar
1 vote
0 answers
314 views

How to debug program creating RAW socket?

For example I have this program: int main() { int sockfd = ::socket(AF_INET, SOCK_RAW, IPPROTO_ICMP); if ( sockfd == -1 ) printf("Error\n"); else printf("Success\n"); return 0; } ...
Rikitikitavi's user avatar
1 vote
1 answer
1k views

sudo netstat -antp not showing PID

i am testing stuff with sockets and i encountered that strange case : i coded i very simple tcp server in c, i made it block after accept(), just to see what happen when accepting multiple connection ...
joseph M'Bimbi-Bene's user avatar
1 vote
0 answers
201 views

Firewall : Is inbound required for getting response while Outbound rule already there?

I developed one MVC web application which have Web APIs and hosted in Amazon Instance and one windows application for calling those APIs for getting response from that server. Both Web and Windows ...
Abhishek Parmar's user avatar
1 vote
0 answers
2k views

ethernet interface on Linux drops packets

I'm trying to capture some Ethernet frames with Linux. Some of these packets/frames are invalid and contain corrupted data. For example an Ethernet frame contains the type 0x0800 which is IPv4, but ...
GNA's user avatar
  • 111
1 vote
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63 views

Sending ihex file over UDP using sockets

I am working with IPv6 and UDP sockets using python-2.7. I am particularly focusing on IPv6 Multicasting ff02::1 where every Link-Local address device (with fe80::) responds to queries from a central ...
Shan-Desai's user avatar
1 vote
1 answer
2k views

How to use multiple network interfaces?

I need to use multiple network interfaces in a C program with sockets. My interfaces are wlan0 and eth0. When I connect eth0, the ping through wlan0 returns "Host unreachable", and consequently the ...
Sceik's user avatar
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1 vote
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Route only on output chain?

I have two machines A and B. I want to send iperf traffic from A to B, but first have it route through a userspace program on A. I did this with a tunneling device: therefore, I used the command ip ...
Ashkay's user avatar
  • 111
1 vote
0 answers
420 views

linux + what are the messages bad tty under /var/log/messages file

under /var/log/messages I see the following messages "bad tty" what the meaning of these messages? second is it caused because some application that called - owstd ? as we can see from the log? ...
maihabunash's user avatar
1 vote
1 answer
933 views

Emulate console by sending data on one UDP port, and receive text from another

I'm trying to establish a “console-like” connection with a National Instruments cRIO-FRC. It broadcasts its console output onto 255.255.255.255, UDP port 6666. I can listen to it with: socat UDP-...
Alexander's user avatar
  • 374
1 vote
1 answer
889 views

websocket responses appear to be cut off

So my websocket server (socket.io) is sending JSON data to my clients who connect with their web browsers (e.g. Firefox). It works fine when I am sending short responses. However, when I send a ...
Eamorr's user avatar
  • 227
1 vote
0 answers
3k views

Re-stream (forward) UDP-Live-Video-Stream (using winsock) reduce video quality?

So, I used ffmpeg to stream the live webcam using UDP protocol to port 1111 : ffmpeg -f dshow -i video="Lenovo EasyCamera" -f mpegts udp://localhost:1111 When I played it directly by ffplay from ...
David Tran's user avatar
1 vote
0 answers
1k views

Mysql socket error 2002 on Linux Mint - Access denied

My apache and xampp servers are running on port 2145 and 16443 respectively. sudo /opt/lampp/lampp restart Restarting XAMPP for Linux 1.8.2-5... XAMPP: Stopping Apache...ok. XAMPP: Stopping MySQL......
Lakshminarayanan Guptha's user avatar
1 vote
1 answer
1k views

systemd: starting service that depends on sockets does not work

I'm using systemd to start a WiFi and power monitor service script that scans for an SSID, brings up the network and an SSH tunnel and does a few other tasks. Much to my surpise it doesn't always ...
carveone's user avatar
  • 327
1 vote
1 answer
1k views

Linux Kernel TCP socket functions

So I have been looking through the Linux Kernel v3.8.0-19-generic source code and I noticed that the proto struct, whose members are virtual functions for socket operations depending on the particular ...
Mr X's user avatar
  • 215
1 vote
0 answers
197 views

Communicate a button click event with sockets

Desire: I have a device or micro-controller i'll call it a mc that I need to communicate to when a web page button is clicked using sockets. MC1 <button id ='on1' name='mc1'>On</button> &...
tyler's user avatar
  • 193
1 vote
1 answer
959 views

Can Connectify Dispatch be used for video streaming?

Here is my situation. We are specialized in video producing local sports for web-streaming. In most cases clients provide us with poor bandwidth, which is absolutely critical for us. There is a ...
Ievgenii Larin's user avatar