4 votes

How does remote users connect to a device on a local network behind NAT without port forwarding or VPN?

In most cases, the internal device behind the NAT initiate the connection to a remote server on the internet. Then the person who need to administrate the device connect to this server and use the ...
S. Brottes's user avatar
  • 1,177
4 votes
Accepted

My Ports are always Occupied and no Software Shows why (netstat, TCPView)

Thanks you very much guys(@frank-thomas , @harrymc and @daniel-b) with your help and guidance I Finally could figure out the problem and solutions for fixing it: Part 1 of Solution After I read part ...
DeDifferentOne's user avatar
2 votes

Repair RJ45 socket after plugging in RJ11

Get magnifying glass & torch… see what damage they did. With the power off, use a pin/cocktail stick/watch screwdriver/needlenose pliers to try straighten it. If it's truly mashed, then your next ...
Tetsujin's user avatar
  • 49.6k
2 votes

esptool.py PermissionError while configuring serial port

I got a new batch of NodeMCU's and was not able to connect and upload code from Arduino IDE. My CH341 driver in windows 11 was automatically updated recently!. i found a driver from 2019 https://...
erling hviid's user avatar
2 votes
Accepted

How to reserve port number and avoid other applicationsto use this specific port number?

The article How do I reserve ports for my application? has several possibilities. One answer is that the following command will prevent the port from being allocated, but will not stop a program from ...
harrymc's user avatar
  • 481k
2 votes

Can I use this SSD on this motherboard

No, your mainboard does not have M.2 slots. Because it is so old, its firmware probably also does not support NVMe. Next time, check before buying. All is not lost however: Your mainboard has a PCI ...
Daniel B's user avatar
  • 63.1k
2 votes
Accepted

MySQL Docker container on Plesk isn't accesible from the exterior

I was facing exactly the same problems and it was driving me crazy. Thank you for posting this, otherwise I would still be searching. I was suspecting a problem with our hardware firewall, but it was ...
christian's user avatar
1 vote

External port checking services claim my port is closed even though I opened it

It could that tool is blocked in the network of your ISP, or that your ISP blocks port checking. There are enterprise/telco carrier firewalls who can block that and most consumer grade ISPs have that ...
Turdie's user avatar
  • 165
1 vote

Understanding how ports work and how are they different from processes?

Very simplified: Consider a multi-party house with numbered apartments. The IP address is the street name + house number. The port is the number of the apartment. The application is what is happening ...
Steffen Ullrich's user avatar
1 vote

Do I risk damage my usb port when connecting two laptop using regular phone cable (usb A to usb C)

Similar to how micro-USB (regular versus "OTG") cables work, standards-compliant A-to-C cables will have a specific resistor on one of the additional pins on the 'C' end to indicate whether ...
u1686_grawity's user avatar
1 vote
Accepted

How to start a script when there is incoming traffic on a specified port?

This functionality is not available in Windows, so you will need to create yourself a listener program on this port that will do some action upon receiving some specific input text. To get you started,...
harrymc's user avatar
  • 481k
1 vote
Accepted

Why can two containers in host network namespace both bind to the same port?

It's mostly the same way you can have multiple sessions on a single port port from the same client. Connections use a socket pair (which includes a unique client-side ephemeral port) to identify ...
Cpt.Whale's user avatar
  • 7,756
1 vote
Accepted

How to make local application accessible for other pc in my local network

A URL must be sent to a web-server to be handled, which is why it worked for you after you added NGINX. It's possible for an application to open a socket on a port and listen for incoming data, but ...
harrymc's user avatar
  • 481k
1 vote

Can't use SSH with any port except 22

@davidgo and @harrymc were on the right track - My VPS provider has a firewall implemented outside of the actual VPS, with only port 22 exposed. Adding a new "allow" rule through the VPS ...
jofre's user avatar
  • 31
1 vote
Accepted

How to find open port on specific IP address in Windows 10?

The program netstat is for displaying open and connected ports and sockets on local machine. To scan and get open ports on remote machine you can use nmap. The command is something like: nmap <IP ...
Romeo Ninov's user avatar
  • 6,295
1 vote

Firewalld: allow only certain source and destination port pairs

Apparently firewalld is not designed that way. It doesn't contain an easy way to limit destinations. (If you consider rich rules not being an easy way :) ) The RedHat documentation states (I added ...
elysch's user avatar
  • 133
1 vote

Open multiple firewall ports in CentOS7

Even though this is a very old question, it can get really "interesting", so I thought I should answer it. Every possible port in a single line # simple firewall-cmd --add-port={80,443}/tcp ...
Vladan's user avatar
  • 177
1 vote

Test if a port on a remote system is reachable (without telnet)

Most Linux systems do come installed with Python3 these days, you can use a script like this: import socket def check_conn(): conn_data = [ ('xyz.abc.int', '10.20.200.10', 443), ('...
Saikat's user avatar
  • 405

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