AngryHacker AngryHacker - 1 year ago 248
ASP.NET (C#) Question

How do I get the kestrel web server to listen to non-localhost requests?

I've deployed my c#, 5, mvc 6 app to a windows 2008 server. I've fired up

dnx web
and it is listening to port 5000 and works fine when accessing from local computer.

How do I get it to listen to non-localhost requests?

P.S. This question is not a duplicate of refers to pre RC1 when hosting.ini actually had an .ini format. Now, it's JSON and I can't find any documentation on what should actually be in it.

P.P.S. The real solution is in the non-accepted answer to the linked question, with a massive caveat. Steps:

  1. Change your project.json per the linked answer.

  2. Publish your project to your server.

  3. On the server, go to ...\approot\src\YourProject folder and open a command window there.

  4. Run
    dnx web
    - it will fail

  5. Run
    dnu restore

  6. Run 'dnu build`

  7. Run 'dnx web` - the web server should now start fine

Answer Source

The default configuration file used by Kestrel server is hosting.json. The name was changed multiple times in different beta versions. If you use now project.json with the following "command" section

"commands": {
    "web": "Microsoft.AspNet.Server.Kestrel"

then during starting the server from the command line by

dnx web

the file hosting.json will be read. The file

    "server.urls": ""

will configure the server to listen 5000 on every IP4 address. The configuration

    "server.urls": "http://::5000;"

will inform to listen 5000 on both IP4 and IP6 address.

One can specify alternative configuration files by usage ASPNET_ENV environment variable or by the usage of --config myconfig1.json (or config=myconfig1.json). For example you can use

SET ASPNET_ENV=Development

and to create hosting.Development.json file with specific configuration. Alternatively you can use project.json with

"commands": {
    "web": "Microsoft.AspNet.Server.Kestrel"
    "webProd": "Microsoft.AspNet.Server.Kestrel --config prod.json"

and start the server by usage

dnx webProd

I have to remind additionally that it could be required that you allow to additionally listen and to register (to start dnx web). It's required because of the firewall and the local security of listening new TCP/HTTP ports. Something like below should make local registering and listening of 5000 port for everybody (IPv4 and IPv6):

netsh http add iplisten ipaddress=
netsh http add iplisten ipaddress=::5000
netsh http add urlacl url=http://+:5000/ user=\Everyone

To be more secure you can adjust the above configuration to grant minimal rights.

UPDATED: Thanks @BlaneBunderson. One can use * instead of IP address (like http://*:5000) to listen on any IP4 and IP6 addresses from any interface. One should be carefully and not use http://*:5000;http://::5000, http://::5000;http://*:5000, http://*:5000; or http://*:5000; because it will require to register IP6 address :: or IP4 address twice.

Corresponds to the announcement

Technically, any hostname that isn't "localhost" or a valid IPv4 or IPv6 address will cause Kestrel to bind to all network interfaces.

I think that the behavior could be changed in the future. Thus I would recommend to use only *:5000, and ::5000 form for registering of any IT address.

UPDATED 2: ASP.NET Core RC2 changes (see the announcement) the behavior of loading the defaults. One have to make changes in the Main to load the settings from hosting.json and the command line parameters. Below is an example of the usage

public static void Main(string[] args)
    var config = new ConfigurationBuilder()
        .AddJsonFile("hosting.json", optional: true)
        .AddEnvironmentVariables(prefix: "ASPNETCORE_")

    var host = new WebHostBuilder()
        .UseUrls("http://*:1000", "https://*:1234", "")


The above code use three bindings: "http://*:1000", "https://*:1234", "" by default instead of usage the default port 5000 by default (to be exact the usage of http://localhost:5000). The call of .UseConfiguration(config) are made after .UseUrls. Thus the configuration loaded from hosting.json or the command line overwrite the default options. If one remove .SetBasePath(Directory.GetCurrentDirectory()) line then the hosting.json will be loaded from the same directory where the application dll will be compiled (for example bin\Debug\netcoreapp1.0).

One can use execution like

dotnet.exe run --server.urls=

to overwrite the default settings (from UseUrls) and the settings from "server.urls" property of hosting.json if it's exist.

In the same way one could overwrite the ULR settings by setting the environment variable

set ASPNETCORE_SERVER.URLS=http://localhost:12541/

then the default start of the application using dotnet.exe run will use http://localhost:12541/ for binding.

You can find here an example of the usage of HTTPS binding.

Recommended from our users: Dynamic Network Monitoring from WhatsUp Gold from IPSwitch. Free Download