17

How can I force Windows to re-scan for available wireless networks from the command line?

(i.e. I'm looking for the command-line equivalent of pressing F5 on the GUI.)

4
  • Does typing the command and pressing the up button + enter not work, or are you using it as part of a larger command? – cutrightjm Mar 14 '15 at 2:11
  • 1
    @ekaj: Typing "the command"? What command? – user541686 Mar 14 '15 at 2:32
  • netsh wlan show networks... add mode=bssid on the end to show the channels, encryption types, and rates – cutrightjm Mar 14 '15 at 3:00
  • 3
    @ekaj: That doesn't refresh anything, it just shows the cached data. – user541686 Mar 14 '15 at 3:03
11

I've been looking for the same thing for a while now, unfortunately I can't seem to find anything in the netsh utility to do this. The best solution I was able to come up with was to disable then re-enable the interface through the netsh commands. There's a small delay (1-2 seconds) after enabling the interface where it won't list any networks, but that shouldn't be too hard to workaround.

I'm using the following commands:

netsh interface set interface name="<NIC name>" admin=disabled
netsh interface set interface name="<NIC name>" admin=enabled
netsh wlan show networks

Edit: How to get then the "<NIC name>", i.e., the Network Interface Card name.

First of all use the command netsh wlan show networks

If the wlan is enabled you will get a message like this

C:\Users\user1>netsh wlan show networks

Interface name : WiFi
There are 2 networks currently visible.

SSID 1 : Cross
    Network type            : Infrastructure
    Authentication          : WPA2-Personal
    Encryption              : CCMP

SSID 2 : WLAN-0A8E41
    Network type            : Infrastructure
    Authentication          : WPA2-Personal
    Encryption              : CCMP

So you see, in this case, the interface name is WiFi Now, you can proceed as explained above, for example to disable the wlan card:

netsh interface set interface name="WiFi" admin=disabled

And so on. :)

6

I wrote a small (~2 KiB) WlanScan.exe program to do this.

Here's the base64 (32-bit version):

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

You can save it to a file from PowerShell like this (save the Base64 to WlanScan.txt first):

Set-Content -Path "WlanScan.exe" $([Convert]::FromBase64String($(Get-Content -Path "WlanScan.txt"))) -Encoding Byte

Here's the source code:

#include <tchar.h>
#include <Windows.h>

#ifndef __CRT_STRINGIZE
#define __CRT_STRINGIZE(Value) #Value
#endif
#ifndef _CRT_STRINGIZE
#define _CRT_STRINGIZE(Value) __CRT_STRINGIZE(Value)
#endif

enum { WLAN_NOTIFICATION_SOURCE_ACM = 0x00000008 };
typedef enum _WLAN_NOTIFICATION_ACM { wlan_notification_acm_start, wlan_notification_acm_autoconf_enabled, wlan_notification_acm_autoconf_disabled, wlan_notification_acm_background_scan_enabled, wlan_notification_acm_background_scan_disabled, wlan_notification_acm_bss_type_change, wlan_notification_acm_power_setting_change, wlan_notification_acm_scan_complete, wlan_notification_acm_scan_fail, wlan_notification_acm_connection_start, wlan_notification_acm_connection_complete, wlan_notification_acm_connection_attempt_fail, wlan_notification_acm_filter_list_change, wlan_notification_acm_interface_arrival, wlan_notification_acm_interface_removal, wlan_notification_acm_profile_change, wlan_notification_acm_profile_name_change, wlan_notification_acm_profiles_exhausted, wlan_notification_acm_network_not_available, wlan_notification_acm_network_available, wlan_notification_acm_disconnecting, wlan_notification_acm_disconnected, wlan_notification_acm_adhoc_network_state_change, wlan_notification_acm_profile_unblocked, wlan_notification_acm_screen_power_change, wlan_notification_acm_profile_blocked, wlan_notification_acm_scan_list_refresh, wlan_notification_acm_end } WLAN_NOTIFICATION_ACM, *PWLAN_NOTIFICATION_ACM;
typedef enum _WLAN_INTERFACE_STATE { wlan_interface_state_not_ready, wlan_interface_state_connected, wlan_interface_state_ad_hoc_network_formed, wlan_interface_state_disconnecting, wlan_interface_state_disconnected, wlan_interface_state_associating, wlan_interface_state_discovering, wlan_interface_state_authenticating } WLAN_INTERFACE_STATE, *PWLAN_INTERFACE_STATE;
typedef struct _WLAN_INTERFACE_INFO { GUID InterfaceGuid; WCHAR strInterfaceDescription[256]; WLAN_INTERFACE_STATE isState; } WLAN_INTERFACE_INFO;
typedef struct _WLAN_INTERFACE_INFO_LIST { DWORD dwNumberOfItems; DWORD dwIndex; WLAN_INTERFACE_INFO InterfaceInfo[1]; } WLAN_INTERFACE_INFO_LIST;
typedef struct _WLAN_NOTIFICATION_DATA { DWORD NotificationSource; DWORD NotificationCode; GUID InterfaceGuid; DWORD dwDataSize; void *pData; } WLAN_NOTIFICATION_DATA, *PWLAN_NOTIFICATION_DATA;
typedef void WINAPI WLAN_NOTIFICATION_CALLBACK(WLAN_NOTIFICATION_DATA *, void *);

typedef struct wlan_scan_finished_context { WLAN_INTERFACE_INFO_LIST *interface_list; HANDLE semaphore; } wlan_scan_finished_context;
static void WINAPI wlan_notification_callback(WLAN_NOTIFICATION_DATA *data, void *context)
{
    if ((data->NotificationSource | WLAN_NOTIFICATION_SOURCE_ACM) == WLAN_NOTIFICATION_SOURCE_ACM)
    {
        if (data->NotificationCode == wlan_notification_acm_power_setting_change || data->NotificationCode == wlan_notification_acm_scan_complete)
        {
            wlan_scan_finished_context *const ctx = (wlan_scan_finished_context *)context;
            if (ctx)
            {
                for (unsigned int i = 0; i != (ctx->interface_list ? ctx->interface_list->dwNumberOfItems : 0); ++i)
                {
                    if (memcmp(&ctx->interface_list->InterfaceInfo[i].InterfaceGuid, &data->InterfaceGuid, sizeof(data->InterfaceGuid)) == 0)
                    {
                        ctx->interface_list->InterfaceInfo[i].isState = (WLAN_INTERFACE_STATE)(ctx->interface_list->InterfaceInfo[i].isState | (data->NotificationCode << 16));
                    }
                }
                if (ctx->semaphore) { long prev; ReleaseSemaphore(ctx->semaphore, 1, &prev); }
            }
        }
    }
}

int _tmain(int argc, TCHAR *argv[])
{
    (void)argv;
    unsigned int result;
    if (argc > 1) { result = ERROR_INVALID_PARAMETER; }
    else
    {
        HMODULE const wlanapi = LoadLibrary(TEXT("wlanapi.dll"));
        if (wlanapi)
        {
#define X(Module, Return, Name, Params) typedef Return Name##_t Params; Name##_t *Name = (Name##_t *)GetProcAddress(Module, __CRT_STRINGIZE(Name));
            X(wlanapi, DWORD WINAPI, WlanCloseHandle, (HANDLE hClientHandle, void *pReserved));
            X(wlanapi, DWORD WINAPI, WlanEnumInterfaces, (HANDLE hClientHandle, void *pReserved, struct _WLAN_INTERFACE_INFO_LIST **ppInterfaceList));
            X(wlanapi, void WINAPI, WlanFreeMemory, (void *pMemory));
            X(wlanapi, DWORD WINAPI, WlanOpenHandle, (DWORD dwClientVersion, void *pReserved, DWORD *pdwNegotiatedVersion, HANDLE *phClientHandle));
            X(wlanapi, DWORD WINAPI, WlanRegisterNotification, (HANDLE hClientHandle, DWORD dwNotifSource, BOOL bIgnoreDuplicate, WLAN_NOTIFICATION_CALLBACK funcCallback, void *pCallbackContext, void *pReserved, DWORD *pdwPrevNotifSource));
            X(wlanapi, DWORD WINAPI, WlanScan, (HANDLE hClientHandle, const GUID *pInterfaceGuid, const struct _DOT11_SSID *pDot11Ssid, const struct _WLAN_RAW_DATA *pIeData, void *pReserved));
#undef X
            DWORD version;
            HANDLE handle = NULL;
            result = WlanOpenHandle ? WlanOpenHandle(1, NULL, &version, &handle) : ERROR_PROC_NOT_FOUND;
            if (result == ERROR_SUCCESS)
            {
                WLAN_INTERFACE_INFO_LIST *interface_list = NULL;
                result = WlanEnumInterfaces ? WlanEnumInterfaces(handle, NULL, &interface_list) : ERROR_PROC_NOT_FOUND;
                if (result == ERROR_SUCCESS)
                {
                    wlan_scan_finished_context context = { interface_list, CreateSemaphore(NULL, 0, (LONG)interface_list->dwNumberOfItems, NULL) };
                    DWORD prev;
                    unsigned int nwait = 0;
                    unsigned long const register_notification_result = WlanRegisterNotification ? WlanRegisterNotification(handle, WLAN_NOTIFICATION_SOURCE_ACM, FALSE, wlan_notification_callback, &context, NULL, &prev) : ERROR_PROC_NOT_FOUND;
                    for (unsigned int i = 0; i != interface_list->dwNumberOfItems; ++i)
                    {
                        unsigned int const result_i = WlanScan ? WlanScan(handle, &interface_list->InterfaceInfo[i].InterfaceGuid, NULL, NULL, NULL) : ERROR_PROC_NOT_FOUND;
                        interface_list->InterfaceInfo[i].isState = (WLAN_INTERFACE_STATE)(interface_list->InterfaceInfo[i].isState & 0xFFFF);
                        if (result_i == ERROR_SUCCESS) { ++nwait; }
                        else { interface_list->InterfaceInfo[i].isState = (WLAN_INTERFACE_STATE)(interface_list->InterfaceInfo[i].isState | (result_i << 16)); }
                    }
                    while (nwait > 0)
                    {
                        WaitForSingleObject(context.semaphore, INFINITE);
                        --nwait;
                    }
                    for (unsigned int i = 0; i != interface_list->dwNumberOfItems; ++i)
                    {
                        unsigned int const result_i = interface_list->InterfaceInfo[i].isState >> 16;
                        if (register_notification_result == ERROR_SUCCESS && result_i != ERROR_SUCCESS)
                        { result = result_i; }
                    }
                    if (result == ERROR_SUCCESS && register_notification_result != ERROR_SUCCESS) { result = ERROR_IO_PENDING; }
                    if (context.semaphore) { CloseHandle(context.semaphore); }
                    WlanFreeMemory ? WlanFreeMemory(interface_list) : ERROR_PROC_NOT_FOUND;
                }
                WlanCloseHandle ? WlanCloseHandle(handle, NULL) : ERROR_PROC_NOT_FOUND;
            }
        }
        else { result = (unsigned int)GetLastError(); }
    }
    return (int)result;
}
6
  • Can't believe no one had even upvoted this answer! Yes it requires a C++ compiler, like Visual Studio 2015's free Community Edition. But it compiled without a hitch and does exactly what the OP asked for. Well done Mehrdad! – Gabe Halsmer Jun 2 '19 at 17:58
  • @GabeHalsmer: Thanks! It does exactly what the OP asked because... I'm the OP ;) I only posted this 2-3 weeks ago so I guess nobody's seen it yet. – user541686 Jun 2 '19 at 20:45
  • I see that you attached the Base64 encoding of the binary code, may I ask you how to create the executable file on Windows by saving this Base64 code? Can I do it from terminal, for example using the PowerShell? Or do you suggest some special editor to do this? – Kubuntuer82 Aug 26 '19 at 17:48
  • 1
    @Kubuntuer82: From within PowerShell, you can do Set-Content -Path "WlanScan.exe" $([Convert]::FromBase64String($(Get-Content -Path "WlanScan.txt"))) -Encoding Byte. From outside PowerShell, you can also use piping to call PowerShell if that's easier: powershell -command "$b = [Convert]::FromBase64String([Console]::In.ReadToEnd()); $s = [Console]::OpenStandardOutput(); try { $s.Write($b, 0, $b.Length); } finally { $s.Close(); }" < WlanScan.txt > WLANScan.exe. I'll add it to the answer. – user541686 Aug 26 '19 at 20:19
  • This is a great solution. It would be great to be able to do this in pure PowerShell and pinvoke'ing .NET – MKANET Dec 9 '19 at 2:23
4

The networks are updated only when a scan is completed by your WiFi card. The NETSH command does not request a scan; it only displays the cached results of the last scan.

Opening the Windows network list from the taskbar updates the results because the taskbar network tool happens to request a scan when it's opened.

There is no NETSH command to request a scan like this. You would have to write some code, leveraging either the Win32 WlanScan function (C# wrappers exist if you prefer that), or the WinRT ScanAsync function.

(Adapted/updated from the source.)


Related:

2

I know I am a little late to the party, but another way of doing this is to restart the wlansvc service.

Get-Service wlansvc | Restart-Service

Unfortunately, this can only be done from an elevated prompt though.

0

Extending this answer, here's a batch script to automate:

@ECHO OFF
for /f "tokens=*" %%a in ('netsh wlan show networks ^| grep -oP "Interface\s+name\s*:\s*\K(.*)"') do set "interface_name=%%a"
netsh interface set interface name=%interface_name% admin=disabled
netsh interface set interface name=%interface_name% admin=enabled
netsh wlan show networks

make sure to run it as administrator.

0
0

I took the code from user541686's answer and put it into a small python script with DLL's. You can get it here and run python scan.py -once -logger-level=quiet to force a re-scan :).

EDIT

I didn't realize that there's already a python package that does this exact thing...

Apparently with winwifi you can just do wifi scan and it will do a force re-scan and then call netsh

0

I'm currently running Windows 10 Home version 20H2, and I was able to force a rescan by opening the available networks list from the taskbar using this command:

explorer.exe ms-availablenetworks:

I have a batch that connects to a specific network; but sometimes, a rescan is required to cause that network to show up as an available network. In the past when a rescan was necessary, my batch would fail to connect to the network. I could manually open the available networks list and then execute the batch with success.

Now with the command above included, my batch will open the available networks list thereby forcing a rescan before attempting the connection. I haven't tested it extensively. I imagine a wait after opening the list but before attempting the connection may be necessary.

I found this command here.

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