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In Aspnet.Core, can we change port number?

I work on aspnet core web api project. I will publish this project to remote server. When Kestrel is running, default port is 5000 or anythink like this.
I want to change this port to 80 or 8080. Can I do that?
When I try to change from launchSettings, I get this error:
System.IO.IOException: 'Failed to bind to address http://localhost:80.'

Your problem may be because you already have another web server running on your system (e.g. IIS) that is already binding to port 80.
You can check with this powershell command:
Get-Process -Id (Get-NetTCPConnection -LocalPort 80).OwningProcess
This command will show you what process is listening on port 80. If nothing is listening, it will return an error.

Debugging Akka.NET remote connections (Cant connect - Failed to bind)

Using the example Chat Server/Client project available as part of the Akka.NET source code I have attempted to modify it such that it would successfully work over two computers on my network.
I have two systems that are connected via a router like this
192.168.0.29 (Server) <---------------| Router |---------------> 192.168.0.52 (Client)
I then have two actor systems that are configured like this:
Server:
akka {
actor {
provider = remote #Specify remote provider
}
remote {
dot-netty.tcp {
port = 666 #Akka server port number
hostname = 0.0.0.0 #Bind to all local network interfaces
public-hostname = 192.168.0.29 #Expose public IP to enable correct routing of public messages.
}
}
}
Client:
akka {
actor {
provider = remote
}
remote {
dot-netty.tcp {
port = 0 #Tell Akka that this is a client connection/use random port.
hostname = 192.168.0.29 #Tell Akka.NET which remote instance to connect to
}
}
}
Unfortunately, while I am able to successfully connect to the chat server locally, no matter how I configure my Hocon I cannot seem to get the remote instance to bind to my server actor located on the machine 192.168.0.29.
The specific error message that I receive
[ERROR][27/11/2019 4:58:36 PM][Thread 0004][Akka.Remote.Transport.DotNetty.TcpTransport] Failed to bind to 192.168.0.29:0; shutting down DotNetty transport.
Cause: System.Net.Sockets.SocketException (10049): The requested address is not valid in its context
at System.Net.Sockets.Socket.UpdateStatusAfterSocketErrorAndThrowException(SocketError error, String callerName)
This error message suggests to me that there is no available socket that Akka.NET can access.
Ironically enough, some time ago I asked a very similar question which at the time helped me resolve my connectivity issues but I never used Akka.NET till recently again.
I note that both machines have their firewalls turned off and can successfully ping each other, I have also played around with all various combinations of settings.
The original source code to the Akka.NET server/client application is located here, my current version of it is here.
Could anyone provide any insight into what I might be doing wrong and how I can improve my debugging of Akka.NET remote connections? For example is there a way that I can verify that the Actor system on server 192.168.0.29 is accessible from 192.168.0.52 externally?

Haha, and literally 5 minutes after posting my question I was finally able to determine the solution (although its not ideal).
The solution was the realisation that when you instantiate the ActorSystem on the client application you are NOT actually connecting the local actor system to the remote system BUT rather creating a local instance of an actor system which itself is listening on a random port.
The remote connection itself occurs when you create an ActorSelection() reference.
So all I needed to do was change my client hocon from
hostname = 192.168.0.29
TO
hostname = 192.168.0.52
However this creates one final (albeit rather small) problem. I now need a different hocon file for an instance running locally vs an instance running remotely. Admittedly this could probably be addressed through code....
I'd be happy to mark as the solution someone who might be able to propose something that addresses this issue.

'No connection could be made because the target machine actively refused it'

I am working on a 'Smart Device Project' using .Net Framework 3.5. I am trying to connect to some Java SOAP services on a remote server.
In order to do that, I added 'Web References' to my project.
When I try to call my web service I get a WebException 'Unable to connect to the remote server' with the inner exception being 'No connection could be made because the target machine actively refused it'.
I searched quite a lot on the Web and StackOverflow and found a lot of ASP configuration and 'Unavaliable port' answers, but as I have another application using the exact same Service successfully, I can't get why the new one isn't getting through (It did sometimes through my tests so I suppose my client implementation isn't that bad)
I tried to look if there was some connection issue on the port by using some TcpClient:
System.Net.Sockets.TcpClient client = new System.Net.Sockets.TcpClient();
try
{
client.Connect("myServerName", 8087);
MessageBox.Show("Success");
} catch (Exception ex)
{
MessageBox.Show("Failure");
}
finally
{
client.Close();
}
This connection succeed.
Here is a sample on how I call my WebService:
WSServiceExtended srv = new WSServiceExtended();
srv.Proxy = new System.Net.WebProxy();
ServeurWSI wsi = new ServeurWSI();
srv.Url = "http://myServerName:8087/myServerApp/services/myService";
wsr = srv.login(wsi);
The service is called 'Extended' because I overrided the auto-generated one in order to add Cookie managment since I am using the Compact Framework. Following the sample in this thread:
https://social.msdn.microsoft.com/Forums/en-US/34d88228-0b68-4fda-a8cd-58efe6b47958/no-cookies-sessionstate-in-compact-framework?forum=vssmartdevicesvbcs
EDIT:
I made some new tests with the Web references and got it to work.
When I add the Web Reference, I have to put some Url to the Web Service. When I set it with the actual hostname instead of the 'localhost' everything is fine.
But then, since I set it manually to the real address just before the call, it shouldn't matter
srv.Url = "http://myServerName:8087/myServerApp/services/myService";
EDIT2:
I might have forgotten some specifics about my environnement.
The Web Services are exposed on my computer on some Tomcat Server.
The application I am working on is also developped on this computer (That's why I can add Web References by putting 'localhost' in the address)
The application is then deployed on a distant device (Windows CE) that will make calls the Web Services through WIFI (There, localhost wouldn't work then)
I tried calling the Web services from other computers successfully.
I'm beginning to think that there might be some differential between the called Url and the one that is set, otherwise, how would I have a difference in behaviour such as the one described in the first edit?
EDIT3:
Well..Seems like it's not a network issue but a .Net compact framework (usage?) issue...
The Url property of the Web Service implementation is simply ignored and the one in the Reference.cs is used in place.
If someone had some idea on how I could troubleshot this, I would really appreciate it.

That error means that you reached a server and the server said "no way". So you're either hitting the wrong server or the wrong port.
I find the telnet client is useful for testing stuff like this. From the command line, you can do:
telnet [servername] [port]
So something like:
telnet myServerName 8087
If it goes to a blank screen, then it connected successfully. If it does not connect, it'll tell you.
The telnet client is no longer installed by default in Windows 7+, so you'll have to install it. See here for instructions: https://technet.microsoft.com/en-ca/library/cc771275
If the connection does open, you could paste in an actual HTTP request to see what happens. A simple GET would look something like this:
GET /myServerApp/services/myService HTTP/1.1
Host: myServerName:8087

One reason for this error can be that the service binds to only a certain IP address. It could well be that the service only listens on the IP that is assigned to the host name, but not on the localhost IP (127.0.0.1).
For example:
If the host myServerName has the public IP 192.168.0.1, your service can choose to listen on all IPs assigned to the host (sometimes specifying 0.0.0.0), or it can specifically listen on 192.168.0.1 only. In that case you will not be able to connect through 127.0.0.1, because the service simply doesn't listen on that IP.
You can "use" this inverse of this feature to make a service accessible only to local clients, not on the public IP-Address, by listening on 127.0.0.1 only, but not on the public IP. This is sometimes used on Linux for example to make MySQL only accessible on the host itself.

I was starting to forget this post but I finally found the problem that was messing things up and it has nothing to do with programmation.
I was doing the calls while the device was connected to the computer via the 'Windows Mobile Device Center' allowing to access the device from Windows.
While connected, the host provided is ignored and all calls on the specified port are handled by the connected computer.
Disconnecting the device allows to communicate properly...

SSH Access using Renci.SSH to MySQL Server

Trying to access a MySQL server using the Renci host SSH library.
I got it working by following the info Creating a forwarded port within an SSH tunnel
Specifically this line got my local port sucessfully set up such that it could be bound:
ForwardedPortLocal port = new ForwardedPortLocal("localhost", 3306, "localhost", 3306));
This is fine, but as I understand it the SSH client is binding to 3306 to receive data back from the server. This is a problem if the user has MySQL already installed as it will be using this port so my service cannot. Of course the service can be stopped but this is not a very friendly process.
I was expecting to be able to pass a High - Ephemeral - Port to listen on for the duration of my connection.
I got a bit confused on which parameter I should pass, having originally thought the second port would be the local port I need to bind to. After extensive experimentation on port configs I am at a loss as to how to handle this.
In addition I tried various overloads but none of the 3 other overloads seemed to produce what I wanted.
Any tips?
Thanks,
Andy

Ok I've resolved this now.
The solution is to modify the MySQL connector string so it uses a Ephemeral port. Picked one at random.
server=localhost; uid=;pwd=; database=; port=14324
Then modify the ForwardedLocalPort to bind to this port.
ForwardedPortLocal port = new ForwardedPortLocal("localhost", 14324, "localhost", 3306);
So we're forwarding the connection to localhost 14324 to localhost 3306 on the remote server.
Next challenge how to ensure that the port I use isn't already bound!!
So to do this use the overload that does not require a port number i.e.
ForwardedPortLocal("localhost", "localhost", 3306)
This will allocate an available Ephemeral port to your process which can be found using:
port.Start();
var portNumber = port.BoundPort;
This can then be added to your MySQL connection string.

Renci ssh.net No connection could be made because the target machine actively refused it

We recently deployed a project into production and are now receiving this error message when we attempt to connect to the external sftp machine, "No connection could be made because the target machine actively refused it". When I was developing the application and testing it, we had no issues connecting to this server.
What would be different? I have administrative privileges and the app pool on the production server does not. I'm not sure if this could be what's causing the issue or if it may be something on the external client's server or their firewall blocking us.

If you are using localhost, specify 127.0.0.1 instead.
When I was using SSH.Net and the host was specified as localhost it threw the exception that the host actively refused the connection WSAECONNREFUSED - 10061. When I specified 127.0.0.1 instead, the connection could be made.
I think this is due to the implementation in SSH.Net:
internal static IPAddress GetIPAddress(this string host)
{
IPAddress ipAddress;
if (!IPAddress.TryParse(host, out ipAddress))
ipAddress = Dns.GetHostAddresses(host).First();
return ipAddress;
}
Which does not resolve a valid hostname for localhost, apparently. C# Interactive yields the following:
> Console.WriteLine(Dns.GetHostAddresses("localhost").First());
::1
The value ::1 does not seem to be a valid IP address for sockets to use.

This is a standard TCP error
WSAECONNREFUSED - 10061
From the Client's point of view it means 'there is no socket at that address listening to that port' (the "actively refused" is a red herring).
i) check the address
ii) check the port
iii) check firewall(s)

From our extensive experience (we offer own networking components) -- it's a firewall problem. The firewall doesn't let your requests pass. It's a common situation when you run say Putty, and it works, but your code doesn't. This is because many firewalls detect well-known applications and let them pass, while preventing other applications.