#StackBounty: #linux #networking #ssh #port-forwarding #port Can access port on public IP but not private

Bounty: 100

I have a PC running a web server on port 8080, and SSHd running on port 22. In my router settings, I have forwarded port 8080 to 80, and set up an ANAME record on my domain pointing to the public IP. I am able to access my site on both my public IP port 80 and on my domain. However, I am not able to access the port using the private IP, or SSH into the PC. The PC has a static IP configured. How can I fix this?


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#StackBounty: #port #tc #filter Using tc to delay packets to several ports

Bounty: 50

After reading several pages like this this and without having a really deep knowledge about the kernel Linux, I am able to filter up to 3 ports using just the three first leaves of the tree.

tc qdisc del dev enp0s3 root //clear any previous configuration
tc qdisc add dev enp0s3 root handle 1: prio //start new queue disc but no classes yet

tc filter add dev enp0s3 parent 1: protocol ip prio 1 u32 match ip dport 6332 0xffff flowid 1:1
tc filter add dev enp0s3 parent 1: protocol ip prio 1 u32 match ip dport 6333 0xffff flowid 1:2
tc filter add dev enp0s3 parent 1: protocol ip prio 1 u32 match ip dport 6334 0xffff flowid 1:3

tc qdisc add dev enp0s3 parent 1:1 handle 30: netem delay 146ms 
tc qdisc add dev enp0s3 parent 1:2 handle 20: netem delay 275ms 
tc qdisc add dev enp0s3 parent 1:3 handle 10: netem delay 258ms 

My problem is that I would like to have more port filters in order to simulate a big scenario with up to 16 possible ports destination. If I try to add a new filter using 10:1 what I get is that the delay is not correct because it starts adding two or more rules and I reach to have more than 1 second delay which is what I don’t want to have.


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#StackBounty: #port #localhost #c# #ubuntu-unity C# Unity Client SocketException: Connection refused

Bounty: 100

I got referred here from StackOverflow.

When I try to run an application on Unity, I get an error (SocketException: Connection refused) on the line:

using (TcpClient tcpClient = new TcpClient("127.0.0.1", port_number))

Then, I tried to look for all opened port in network utility on Mac, and when I telnet 127.0.0.1 port_number on terminal, it was able to connect, but when I try to run the code on Unity, it crashes now instead of throwing that error mentioned in the title.

I don’t think it is a code issue because my teammates are able to run the same program successfully on their machine.

I am using Unity 2019.2.5f1, MacOS Mojave version 10.14.6, and I disabled my firewalls and uninstalled all my VPNs.

I am looking for possible cause of my issue here and what to research to debug this.

Thank you.


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#StackBounty: #ssh #port How to overcome blocked SSH attempt

Bounty: 50

I am trying to SSH to a remote university machine from a library, but I get the error message:

ssh: connect to host remote.machine.edu port 22: Connection refused

I have previously posted about this, and I have also spoken to the network administrator to try to change the port.

The system administrator said:

I have it listening on port 2222, but it looks like that’s being
blocked further upstream.

He said he would try to think of a way around it, but it doesn’t seem like we have a solution currently.

It was suggested to me to SSH over port 443. Is there a reason that 443 would work if 22 or 2222 didn’t?

Any other solutions would also be appreciated.

(The machine is not down).


To clarify:

  • When I SSH to the remote machine everywhere except the library, using the default port (which I guess is 22 from the library error message) it works fine.

  • I’m not sure why the system administrator said he had it listening on port 2222. I assumed that meant that he was trying something different from the 22 that was failing from the library. (Because if it was always 2222, I would NEVER be able to ssh). Either way, he said that it looks like that’s being blocked further upstream.

  • Should I ask him to try to listen on port 443?

  • Is there some different way I can get around the problem?


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#StackBounty: #ubuntu #firewall #android #port #kde-connect KDE Connect Not Working [Ubuntu 16.04] : KDE Connect is not discovering pho…

Bounty: 50

I have installed the KDE Connect application on my desktop and also on my phone [Xiaomi Redmi 3S Prime]. But the desktop application would not detect my phone and vice versa.
I have checked the ports. They are open. There is no firewall installed. I have also tried adding my PC manually by entering the IP address in the Android App and that did not work. I also tried restarting the kdeconnectd daemon but that also didn’t work for me.

EDIT:
Here are the things that I have tried.

  1. Check if the kdeconnectd daemon is running.
    enter image description here

  2. Check if I have the ports blocked and if firewall is enabled.
    enter image description hereenter image description here

  3. Check if KDE Connect is listening on the port.
    enter image description here

Please help with all the solutions you can.

PS. It might seem like a duplicate but I have tried almost all the solutions out there but none of it seems to work for me. Hence, I am here.


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How to check which application is using a particular port?

Source : http://oolacola.blogspot.com/2009/04/how-to-find-out-which-application-is.html

Let’s say that we are looking for port 80 — IIS, Apache and other web servers listen in port 80, so when you are having problems starting Apache, this technique will be useful. Here is the command.

C:>netstat -aon | findstr 80

-a means list all active connections and their ports. -o means include their process IDs. -n means display the port numbers numerically.

The pipe symbol ( | ) means, that instead of the result of netstat being displayed on the screen, feed it’s result to the findstr process — we are looking specifically for the line which has 0.0:80 — you actually don’t need findstr, but I don’t want to scroll down and hunt down manually which app is using port 80. You might see something like this.

TCP 0.0.0.0:80 0.0.0.0:0 LISTENING 560

Aha! now we know that process 560 is using port 80 (that last column right there, is the process ID), you could press CTRL-ALT-DEL now to show the process window, and manually look up which app has the process ID 560, or you could enter ..

C:>tasklist | findstr 560