Questions tagged [socket]

A socket is an abstract network construct with a sending and receiving side. In most modern operating systems (OS) there are device representations, and programming tools to address sockets.

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Loosen heatsink screws not coming out of the socket plate

I recently bought a dual CPU HP z640 off ebay. I got better xeons to replace the ones that came with the workstation, so I took out the daughterboard, unscrewed the screws (always in diagonally ...
20 votes
4 answers
39k views

How do I configure Nginx proxy_pass Node.js HTTP server via UNIX socket?

I am trying to configure a Nginx server to connect to a Node.js HTTP server via a UNIX domain socket. The Nginx configuration file: server { listen 80; location / { proxy_pass http://unix:/...
2 votes
0 answers
100 views

Cannot connect to a port on Ubuntu 22.04 x64

I have MySQL running on port 1835, as proven by running the command: lsof -i:1835 The following was run to open the port on the firewall: ufw allow 1835/tcp ufw enable ufw reload But the port cannot ...
0 votes
0 answers
39 views

Kernel TLS Socket Redirect

Suppose both the client as well as the server are on the same machine and they want to do mTLS. They both choose to offload the TLS to Kernel (kTLS). Now when the key exchange happens, given the ...
0 votes
1 answer
66 views

Can not ExecStart service python script as root on Linux

OS: Ubuntu 20.04.6 LTS I created a service that executes python script checker.py. The problem is this service does not execute python script with root privileges, although sirjay user has root ...
0 votes
0 answers
84 views

TCP_NODELAY for All current sockets in linux

i want lowest latency network with tcp_nodelay., in windows OS we can easily enable TCP_NODELAY through registry of windows. i searched on the red hat website and another website but up to now, my ...
6 votes
2 answers
30k views

Unable to restart a systemctl service remotely as a non root user

I have a systemd.socket named gunicorn.socket which I would like to restart after updating some code on a remote server. I've followed the steps detailed in Allowing a non-root user to restart a ...
1 vote
0 answers
143 views

What does it mean when netstat outputs a dash in pid / program name column?

Here is some lightly modified output from netstat (I removed the addresses and names) a@xxxxx:/app# netstat -p Active Internet connections (w/o servers) Proto Recv-Q Send-Q Local Address ...
-1 votes
1 answer
60 views

How does real server, direct return server (DRS), reply to client if a load balancer (LB) uses port address translation (PAT)?

Direct Return Server overview: The DRS allows real servers to directly reply to a client without going through load balancer (LB). The LB ip (VIP) is configured as a loopback (localhost) ip for the ...
12 votes
0 answers
656 views

How much does FreeBSD accept_filter actually improve performance in a modern world?

I recently learned about FreeBSD's accept_filter socket option which can allow a worker process to avoid context switching by, for example, waiting until a full HTTP request is received with accf_http:...
3 votes
2 answers
9k views

HAProxy max session limit

I have an Amazon OpsWorks stack running HAProxy (balance = source) and several node.js instances running socket.io. It seems HAProxy determines the max session limit for a given instance based on the ...
3 votes
2 answers
5k views

Unable to access 3ware 3dm2 web interface, failed to start listening socket

I am unable to get to the 3ware 3dm2 web interface. When I attempt to execute 3dm2 from the command line, i get the following error "(0x0C:0x0005): Failed to start listening socket". This was working ...
9 votes
7 answers
67k views

ERROR 2002 MYSQL socket /tmp/mysql.sock

A have already read everything about this error but I coundn't solve the problem. ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (38) I'm trying to install ...
0 votes
1 answer
136 views

php-fpm creats only one socket file

I have multiple virtual hosts with unique domain names, users, and root directories for each on Nginx and php8.1-fpm. In the /etc/php/8.1/fpm/pool.d/domain.com.conf contains user = domainuser group = ...
0 votes
1 answer
223 views

Python gethostbyaddr being slow

I'm facing an issue today I can't explain and I'm hoping someone will be able to put me in the right direction. I have a fleet of EC2 servers running a python script. When a user connects to my ...
2 votes
1 answer
692 views

OpenDKIM's UNIX socket and permissions for "others"

Postfix installation procedure created a system user postfix and it's primary group postfix while installation procedure for OpenDKIM created a system user opendkim and it's primary group opendkim. To ...
56 votes
5 answers
97k views

Create Unix Named Socket from the Command Line

Is there a command similar to mkfifo but for domain sockets?
0 votes
2 answers
1k views

Fork connections out from a single socat connection

I have an old legacy application I’m trying to get to work with our semi-modern network. This application sends log messages as HTTP requests (one log per request) but does so over a single TCP ...
0 votes
0 answers
357 views

Portainer can't access docker socket without chmod 666 workaround

Environment: Alpine Linux (3.18) I've got a portainer docker container that can't access the docker socket. I've added my user to the docker group. I make the container with the following command: ...
44 votes
7 answers
54k views

Forward local port or socket file to remote socket file

Quick question - I run two linux boxes, one my own desktop and the other my VPS. For security reasons on the VPS end I opted for socket connections to MySQL (/var/run/mysqld/mysql.sock). I know I can ...
0 votes
2 answers
3k views

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

EDIT: The following describes my original question, but as long as I haven't resolved the issue yet, I thought maybe I should change settings inside the created mysql POD instead of mysql config files ...
12 votes
5 answers
16k views

Sniff UNIX domain socket

I know that some process is writing to a certain unix domain socket (/var/run/asterisk/asterisk.ctl), but I do not known the pid of the sender. How can I find out who is writing to the socket? I have ...
4 votes
1 answer
4k views

Maximum limit of filepointer in php reached and not changeable

I have a server with the current 5.3.x version installed. Since we are running a really simple and small server in php using sockets, that connects to a lot clients using sockets we need to raise the ...
0 votes
0 answers
82 views

PHP Error waiting on socket

I'm getting problems with ssh2 and fread php function that started on a few days. On the apache error log show: ssh2_connect(): Error starting up SSH connection(-9): Error waiting on socket fread(): ...
233 votes
3 answers
240k views

What is the difference between Unix sockets and TCP/IP sockets?

It's from this answer: https://stackoverflow.com/questions/2482411/is-this-pdo-bug-fixed-now/2482424#2482424 When the host is "localhost", MySQL Unix clients use a Unix socket, AKA Unix ...
2 votes
1 answer
944 views

Scaling and Load testing Django Nginx and Gunicorn: 502 Server Error + Resource temporarily unavailable gunicorn.sock

I'm doing load testing with locust to see if my server can handle 1500 users. What I'm using: Django, Nginx, Gunicorn, Postgresql My droplet: 24vCPUs, 128GB RAM, 25GB SSD at about 1100 users I start ...
1 vote
1 answer
4k views

Troubleshooting connection timeouts and SYN_RECV

My DigitalOcean droplet fails very often to connect to different resources, like making a REST call with curl or establish SSH connection. Every time it happens, I can see sockets with SYN_RECV state ...
-1 votes
1 answer
2k views

ping 100% packet loss - can't ping to server

when I try to ping my newly created server it shows: vasanth@vasanth-client:~$ ping -c 4 server.ip.name PING server.ip.name (server.ip.address ) 56(84) bytes of data. --- server.ip.name ping ...
6 votes
2 answers
51k views

Why would a client send a RST packet as reply to a SYN,ACK?

I have a HTTP webservice where sometimes the connection setup fails in a strange way: client sends a SYN packet server sends a SYN,ACK reply client responds with RST In which situations could a ...
2 votes
3 answers
2k views

Installing the Data Plane API in the HAProxy Process Manager

I'm trying to start the Data Plane API on HAProxy boot using the instructions detailed here: https://www.haproxy.com/documentation/hapee/1-9r1/configuration/dataplaneapi/#using-the-haproxy-process-...
1 vote
0 answers
685 views

clamav-daemon doesn't create /var/run/clamd.ctl

I installed clamav-daemon on Debian 11 and when I try to start it, it doesn't create the LocalSocket /var/run/clamd.ctl. LocalSocket in my /etc/clamav/clamd.conf: LocalSocket /var/run/clamav/clamd....
132 votes
8 answers
320k views

How to forcibly close a socket in TIME_WAIT?

I run a particular program on linux which sometimes crashes. If you open it quickly after that, it listens on socket 49201 instead of 49200 as it did the first time. netstat reveals that 49200 is in ...
2 votes
2 answers
9k views

Sar: what does totsck stand for

I'm looking for an explanation of the totsck column for the "sar -n SOCK" output 09:44:06 PM totsck tcpsck udpsck rawsck ip-frag tcp-tw 09:44:09 PM 580 18 5 ...
0 votes
1 answer
109 views

How to track file lifetime using lsof?

I have read article https://tailscale.com/blog/case-of-spiky-file-descriptors/ where author investigates anomalies with the amount of open file descriptors. He said that made snapshot of open files ...
1 vote
1 answer
944 views

Start Apache on-demand using systemd socket activation

I have a local website on Debian 11 which is rarely used so I thought I might want to start Apache using systemd socket activation when visiting the site and then shut down after few minutes of ...
0 votes
1 answer
148 views

How do I setup a SSL certificate for an express.js server behind a load balancer?

I'm restructuring my server structure by splitting them up instead of running everything from one server. I looked here but that just specifies what I were already doing in the original setup with ...
1 vote
0 answers
807 views

Client Listening on 0.0.0.0 when custom network interface doesn't exist?

I'm facing an issue in our environment where I'm starting a ServerSocket (Java), and configuring it to listen on 0.0.0.0. Then I'm creating a network interface, and my client is attempting to connect ...
0 votes
1 answer
909 views

Ansible - No such file error when activating systemctl Podman user socket

I am running an Ansible playbook on a fresh Oracle Linux 8 system. It includes a step where it asks systemctl to activate a user Podman socket like so: - name: Enable podman socket vars: userid:...
1 vote
1 answer
2k views

Which machine is actually closing the TCP socket and why?

I'm working on a C# application, handling TCP sockets. I have a server application (Hercules) on the remote machine, trying to keep a socket open. I have my application on my machine, subscribing to ...
1 vote
0 answers
92 views

Reached pm.max_children, High sockets allocated, No CPU usage

The issue I have a server that reaches pm.max_children (200) without spike in CPU usage. No network traffic (MB out / MB in) but extremely high number of socket allocated that do not get closed. CPU: ...
3 votes
0 answers
221 views

How to tell whether a linux tcp socket had recent activity?

Most of the time, when changing or upgrading a network service, I would do this during maintenance hours but some services are rarely used so it is tempting to just check whether it is currently in ...
0 votes
1 answer
2k views

KVM unix socket file permission for VNC

I'm using kvm-qemu/libvirtd for a bunch of kvms. I'm using vnc for the graphical interface. By default, it listens on a tcp socket. I want to have it listen on a unix socket instead. Looking at some ...
71 votes
7 answers
139k views

How to force MySQL to connect by TCP instead of a Unix socket?

I would like to analyze mysql traffic. Right now, all mysql requests are sent to the MySQL unix socket: unix 2 [ ACC ] STREAM LISTENING 3734388 15304/mysqld /var/run/mysqld/...
1 vote
0 answers
225 views

How to open communication PYTHON socket with a SERVER SOCKET on AWS EC2 to a CLIENT SOCKET on my local pc?

Sorry my english is not good I want to established connexion from my client socket on my local pc to a host server socket on AWS EC2 instance. I'm trying to follow suggestions from here and code from ...
2 votes
1 answer
2k views

Can HAProxy reconnect a websocket to another backend server transparently?

I'm new to HAProxy so this might have an obvious answer but I wasn't able to find it. Consider this setup: two backend web applications; one HAProxy in front of the web applications; many clients ...
2 votes
1 answer
2k views

high traffic websocket/haproxy tuning

i have a pubsub application (mostly chat but some other goodies being pub-ed and sub-ed too) running on node & socket.io. i'm load testing this app by spinning up some other, real large, boxes ...
1 vote
0 answers
53 views

How are Linux ACLs different for files versus sockets

With umask 0022, using default ACL entries default:user::rwx, default:group::rwx, default:mask::rwx and default:other::rwx for a directory, files created with touch (e.g.) have a mask of rw, and ...
1 vote
1 answer
2k views

Servicing ws:// in Node.js via Tomcat and Apache

I've Googled various combinations of keywords but I cannot find a suitable description of what to do to get this to work. Currently, I have a web site running Apache 2 with everything except ports 80 ...
1 vote
1 answer
2k views

Nginx proxying websockets, connections not closed

I'm confused about where the problem is located, but basically I have nginx proxying websocket connections to a backend ruby thin server, which services the connections with the websocket-rails module ...
2 votes
1 answer
3k views

gpsd.socket for chrony does not work

I tried to get more accurate time from gps data using ublox module and centos but it seems gpsd.sock does not work properly to get the data to chrony. am I missing somthing ? [root@info /]# cat /etc/...

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