Questions tagged [port]

A port provides a location for an application to interface with the network. If there is no application that is listening at a particular point, data sent there will never be used.

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1 answer
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Exposing another port for Nginx in DockerFile

I'm new to DockerFile. I want Nginx to be listening on port 8080. so I've written the dockerFile in this way: FROM nginx:1.11-alpine COPY index.html /usr/share/nginx/html EXPOSE 8080 CMD ["nginx", "-...
0 votes
1 answer
2k views

Cannot telnet to a local server

I want to reach a Windows PC on my LAN on a specific port, but it fails and I can't find the reason. Can you spot anything? PC is running Windows 10. I have disabled the Windows Firewall on it (for ...
2 votes
1 answer
509 views

How do I forward a port to a subdomain for non-http services

I am running two minecraft servers on my home network. I want to open them up to the world by forwarding the port. I may possibly add more minecraft servers, but I don't want to keep opening up ports ...
0 votes
1 answer
573 views

Uninstall and reinstall raspberry pi desktop on chromebook

I have a 4GB Raspberry Pi which stopped booting recently. I want to uninstall and reinstall the os so it will boot up fresh. I don't have an adapter, but I do have a chromebook which has an sd card ...
0 votes
1 answer
239 views

Ubuntu server Iptables rerouting not working properly

I am trying to setup a simple node.js express app on ubuntu server. I wanted my app to listen on port :80 but it was throwing errors on startup so i changed it to listen on port :3000 (I don't really ...
48 votes
3 answers
275k views

How to find out what is running on localhost port

I have something running at port 9090 on my local machine. It's probably something I set up long ago and forgot about... how can I find out what it is? I am using Windows 8.
0 votes
1 answer
983 views

DHCP Discover : why don't other hosts reply with ICMP 'port unreachable'

When a host sends a DHCP Discover (port 67, UDP), why don't all the hosts (except the DHCP server) reply with an ICMP 'port unreachable' message. This would cause a huge amount of useless data going ...
0 votes
1 answer
801 views

Why should registered port numbers not be used as public ports? [duplicate]

Registered Ports (1024 - 49, 151) are port numbers that gets registered with IANA for public use. Assume I have a popular application like discord, running on some port using a different protocol ...
0 votes
1 answer
2k views

What exactly is a Registered port [ 1024-49151 ] and how to use it?

I've come across the below definition for registered ports, Registered Ports 1024-49151 are available for registration at IANA for more common purposes since they are available for regular users to ...
0 votes
0 answers
681 views

How to stop process from hogging port 8080?

I am trying to use port 8080, but there is a process that keeps using it, and whenever I kill it, another one takes its place. Here is the result of sudo netstat -naptu | grep 8080 tcp 0 0 ...
7 votes
2 answers
6k views

Can't open port even there is no other applications are listening on it [Windows]

I want to open port 8888 on local Windows environment but no luck. Or how can I check Windows Event Log for failed at opening port 8888? Here is the result of all listening port start with 8xxx ...
41 votes
4 answers
105k views

What port does 'ping' work on?

Is there any particular port number that the ping command works on by default? Also on a Linux system, is there a way to figure out by yourself which port numbers it runs on and configure a different ...
4 votes
5 answers
26k views

How to determine why port 443 is already in use?

I'm running Apache 2.4.10 on a Windows 7 machine and am trying to add SSL connections. Port 80 connections work fine, and I'm trying to add port 443. When the httpd.conf gets Listen 443 added it ...
4 votes
1 answer
1k views

Router being double-NATed by ISP

I am trying to set up an Apache server at my house which can be accessed through port 80 by my home router. I was able to do this a few months ago, and then I took the website down. When I tried to ...
1 vote
2 answers
1k views

Why URL with port number other than 80 gets HTTP traffic?

An example of URL that links to a web hosting control panel: http://example.com:3500 HTTP is port 80. Why does the URL use port 3500? Is it port 3500 or port 80?
147 votes
15 answers
665k views

Manually closing a port from commandline

I want to close an open port which is in listening mode between my client and server application. Is there any manual command line option in Linux to close a port? NOTE: I came to know that "only ...
1 vote
1 answer
6k views

Openwrt port forwarding not working

I have a TP-Link MR3420 router with OpenWRT, and I can't forward port to a destination host in my LAN. In firewall I have set like below: config redirect option name 'ssl' option proto 'tcp' option ...
0 votes
0 answers
399 views

Echo to /dev/ttyUSB0 produces no results

I'm trying to make a POS thermal printer work with linux. As far as I understand it, I can send data to print directly to the printer throgh a port - it's an RS232 with USB adapter. It gets connected ...
0 votes
0 answers
625 views

How to print with a serial port printer in Ubuntu?

I am completely clueless when it comes to printers, ports and things like that so I am just reading and trying to get a printer to work without getting a college degree haha... Basically, I have a ...
0 votes
1 answer
1k views

Why does /etc/network/interfaces disable port enp1s0?

Before installing /etc/network/interfaces, both ports on the PC (enp1s0 and enp2s0) could ping other IPs on the network and google. After installing /etc/network/interfaces and setting the IP address,...
0 votes
1 answer
47 views

Port exhaustion

What does Port exhaustion mean ? and as QA tester? how to test it and what are the expected results ? When I reviewed what the developer wrote : As a developer I want to update the application to use ...
0 votes
1 answer
2k views

Ping from specific port of device

AOA, Hello, I have a device on which Ubuntu-server is installed. I have two ports, connected to LAN and device respectively. When I ping to some IP address it listens through the port not wanted by me ...
0 votes
0 answers
37 views

I am having problems port forwarding

I have looked at guides and solutions online but it seems to not be exactly the same as my problem. I think I have successfully port forwarded but I can't access it from External IP. I can access my ...
0 votes
0 answers
437 views

How can I do a bi-directional Port-Forwarding (flow encapsulation)?

I have two applications: a client and a server which communicate through port 1234. For some reasons this port is blocked on our system but everything works correctly on port 1235 (checked with two ...
0 votes
0 answers
728 views

Port forwarding not working in Fritzbox

I want to expose a tiny web server developed in python using flask package. I run it on my local machine using flask run --host=0.0.0.0 which starts the server locally on port 5000 which it is ...
0 votes
1 answer
5k views

NTP server, port not open

So, I'm trying to install an NTP server on this Windows 10 Home computer. I've tried various tutorials to enable w32time's server mode, and then when that failed I eventually installed Meinberg NTP, ...
0 votes
2 answers
14k views

Block port 111 on centos 7

I am using a server with centos 7 running kvm/virtualization, I access using VNC server. Today I received an warning about my server being used to attack other server using port 111, I am completely ...
0 votes
1 answer
1k views

Telnet port 587

Our IIS hosted system sends Email through an account [email protected]. Sometime ago, my ISP blocked port 25 so it stopped sending, talking to my email provider GoDaddy, they said I can use port 587. ...
1 vote
0 answers
45 views

Port forwarding for MyCloud NAS Device

So I've got a MyCloud NAS device and I used to have port forwarding set up on an old router. I recently moved and have a new ISP so I'm unfamiliar with the jargon used by this one. I've got HTTP port ...
1 vote
2 answers
1k views

How does a host know automatically that on which port number a specific server is listening?

I know DNS tells the IP address of a web address. But how does a client know that on which port that specific website is listening on? Similarly for other services like FTP, Telnet and SMTP. I know ...
-2 votes
1 answer
1k views

Forwarding port 22 on ZTE-ZXHN H1008N

enter image description here I don't understand a single thing in regards to networking. I managed to SSH to my other PC on LAN, but I can't seem to figure out how to open up port 22 in order to be ...
0 votes
0 answers
1k views

Unable to open port 22 for SFTP file transfer (Remote Desktop environment)

I have been given access to Remote Desktop environment where I am supposed to set up file transfer between SFTP server and Remote Desktop storage location. Everything is set up correctly (I am using ...
26 votes
7 answers
117k views

How to kill a process by port on MacOS, a la fuser -k 9000/tcp

On linux I can kill a process knowing only the port it is listening on using fuser -k 9000/tcp, how do I so the same on MacOS?
0 votes
0 answers
30 views

Laptop Only Accepting 3.0 USB

I have been using Dell Inspiron 7567 for the last 2 years. Suddenly a strange issue appeared. Now my laptop is only accepting 3.0 USB. No other than 3.0. Not even mouse. In the device manager, I am ...
0 votes
0 answers
505 views

How to resolve WSL2 port conflict with windows services?

I am on Windows 10 20H2 (Build 19042.867). I also using WSL2 with Ubuntu 20.04 LTS. Recently, after upgrading to SSD, I have a problem entering WSL2 with the following error: wsl error 0xfffffff press ...
2 votes
0 answers
1k views

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 ...
0 votes
0 answers
123 views

I Setup a Bukkit and Spigot Minecraft server and port forwarded it but can't connect from WAN

So I setup a Minecraft server for me and my friends and I am 300% sure I port forwarded it correctly but my friends aren't able to connect to it. When I used an online tool to check wether i have ...
0 votes
1 answer
2k views

Port forwarding not working, tried with telnet

List of my virtual servers: I'm attempting to open the port on my laptop to this port My results from ipconfig: (yes the ips are the same) Even if I turn on DMZ it doesn't work. My router is a ...
0 votes
1 answer
332 views

Access port forwarded services on public interface from LAN (ZTE F660T)

I port forwarded different services on the public interface of my router (ports 22, 80, 443). It works fine when I access the services from another public ip. For example: Computer A (public ip: 1.1....
0 votes
0 answers
352 views

I can't open a port for use with Storj

I'm trying to open a port for create a Storj node (Storj is a decentralized storage cloud for who don't know), so I followed all instructions but I cannot open a port. My router is a Tenda N300, and ...
0 votes
1 answer
639 views

Can't connect remotely to MySQL database over network

I'm trying to connect to a MySQL database that's set up on a Linux Mint installation however I can't connect to it through MySQL Workbench: Failed to Connect to MySQL at 10.0.0.5:3306 with user root ...
0 votes
0 answers
29 views

USB connectors dont recognize device but works

I have a logitech mouse. This mouse was working on every USB-port. But it stopped working on one by one and now I'm able to use it as a normal mouse. But its not recognized with a Logicool app anymore ...
0 votes
1 answer
369 views

Problems With Port Forwarding

hope everyone is doing ok! So I have a problem with port forwarding and I cannot get it to work. I'm trying to port forward on port 25565 and I have also tried other port's like 80, 8080, 3396, 4782, ...
-2 votes
1 answer
251 views

How do I block Port 25 on RedHat 6.4

I need to block port 25 on Rehat 6.4 as Postfix smtpd is using it. I have tried to disable it in the IPtables, but if i do a port scan I can still see the port as open along with port 22 which is fine....
2 votes
3 answers
2k views

What exactly are user ports?

I was a little confused I noticed that: Well-known ports, are predefined ports on servers that are used to connect the client to the server. (that reserved in IANA) Dynamic ports, are ports that the ...
1 vote
0 answers
269 views

Connection refused on port 9283 even though the port is open and listening

I am running a Grocy docker container on a Raspberry Pi 2 [fresh Raspbian install]; the container is running, with port 80 mapped to port 9283 on the host: Verify container is running via docker ps: ...
0 votes
1 answer
83 views

Are these specified ranges a rule for the three types of port numbers?

Various articles as well as the IANA site 1 have stated that the range of three types of ports is as follows: 1-Well-known ports:0-1023 2-User ports:1024-49151 3-Dynamic ports:49152-65535 but in ...
0 votes
1 answer
1k views

Set up port forwarding for 2 devices on same IP?

I am trying to set up port forwarding so that I can access two devices remotely. I have succeeded in setting up the port forwarding, however I can only access one at a time. I access the devices via ...
0 votes
1 answer
209 views

Windows port forwading

I got the following setup on an Windows Server 2012 R2: I have 2 NICs: Nic1 has an public ipv4 address (lets call this 5.5.5.5). Nic2 has an private IP address (192.168.2.10). So now I want to ...
0 votes
0 answers
728 views

After opening port 443 in windows firewall as inbound rule, I cannot see it when I run 'netstat -an'

As an inbound rule on Windows 10 firewall, I added port 443 as TCP connection allowing all types of connections. However, I cannot see it when I run 'netstat -an'. How can I get it so that I see my ...

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