Get all local IP addresses doesn't work on WSL2 using System.Net.DNS.GetHostAddresses

[sipsorcery]

(this issue was originally logged on the WSL2 repo and was verified not to be a WSL2 issue).

Environment

Windows build number: Microsoft Windows [Version 10.0.19041.172]
Your Distribution version: Release:        18.04
Whether the issue is on WSL 2 and/or WSL 1: Linux version 4.4.0-19041-Microsoft (Microsoft@Microsoft.com) (gcc version 5.4.0 (GCC) ) #1-Microsoft Fri Dec 06 14:06:00 PST 2019

Steps to reproduce

Minimal .Net Core project to demonstrate the problem:

using System;
using System.Net;

namespace GetLocalIPAddresses
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Get Local IP Addresses Test:");

            var addresses = Dns.GetHostAddresses(string.Empty);
            Console.WriteLine($"Address count {addresses?.Length}.");

            foreach(var address in addresses)
            {
                Console.WriteLine(address);
            }
        }
    }
}

Expected behavior

Based on documentation here a call to System.Net.DNS.GetHostAddresses with an empty string should return a list of all the local IP addresses.

Windows 10 cmd shell result

>dotnet run --framework netcoreapp3.1
Get Local IP Addresses Test:
Address count 6.
fe80::54a9:d238:b2ee:ceb%21
fe80::3c8d:dbf7:1710:efb4%64
fe80::64dc:7955:ef80:6bc4%33
192.168.11.50
172.29.0.1
172.31.32.1

Ubuntu 18.04.4 LTS vm result

$ dotnet run --framework netcoreapp3.1
Get Local IP Addresses Test:
Address count 2.
192.168.11.41
fe80::20c:29ff:fee7:4ce4

Actual behavior

wsl2 result

$ dotnet run --framework netcoreapp3.1
Get Local IP Addresses Test:
Address count 1.
127.0.1.1
$ ifconfig
ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.11.50  netmask 255.255.255.0  broadcast 192.168.11.255
        inet6 fe80::54a9:d238:b2ee:ceb  prefixlen 64  scopeid 0xfd<compat,link,site,host>
        ether c8:d3:ff:b7:83:26  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eth3: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.31.32.1  netmask 255.255.240.0  broadcast 172.31.47.255
        inet6 fe80::64dc:7955:ef80:6bc4  prefixlen 64  scopeid 0xfd<compat,link,site,host>
        ether 00:15:5d:7a:f6:49  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eth4: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.29.0.1  netmask 255.255.240.0  broadcast 172.29.15.255
        inet6 fe80::3c8d:dbf7:1710:efb4  prefixlen 64  scopeid 0xfd<compat,link,site,host>
        ether 00:15:5d:58:a3:2e  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 1500
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0xfe<compat,link,site,host>
        loop  (Local Loopback)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[ghost]

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[ManickaP]

This seems like #27534 which should be fixed now.
@sipsorcery, could you please try it with 5.0 preview?

[sipsorcery]

Yes I can confirm the issue is fixed in net5.0 preview.

dotnet run --framework net5.0
Get Local IP Addresses Test:
Address count 7.
127.0.1.1
192.168.11.50
fe80::54a9:d238:b2ee:ceb%21
172.31.32.1
fe80::64dc:7955:ef80:6bc4%33
172.29.0.1
fe80::3c8d:dbf7:1710:efb4%64

Apols for not spotting the original issue.