Local Site Found by a Universal device

We have multiple locations with backup hosted sites. These sites are designed to allow the end-user to access the information they need when the network is down. They are set up with a local database and some basic asp.net coding. However, the devices that communicate with the site must be able to go between multiple locations. This means no hard-coded links as the hosting device has a different name at each location. DNS might not be available as well. The chaos this brings! There is a solution though. Here are the requirements for the solution we created.

  1. The hosting server can be a different name, but the IP address must end in the same number. In our example, it is .5
  2. The IP address must be a /24 subnet.
  3. The /site.html must be the same across the board.
    1. For example, the site can be http://10.10.1.5/thissite.html at one location and be http://10.10.13.5/thissite.html at another.

lets look at the powershell script really quickly and break it down.

The Script

$IPaddress = (Get-NetIPConfiguration -Detailed | Where-Object {$null -ne $_.IPv4DefaultGateway})[0].ipv4address.ipaddress
Start-Process -FilePath 'C:\Program Files\Internet Explorer\iexplore.exe' -ArgumentList "https://$($IPaddress.split('.')[0]).$($IPaddress.split('.')[1]).$($IPaddress.split('.')[2]).5/login.aspx"

What we are doing with this script is grabbing a detailed report on all the network IP configurations on the local computer. By default, an active network will have a default gateway assigned to it. This can be statically assigned or it can be automatically assigned. Either way, it goes, it’s assigned.

To narrow down the results we use a where-object command to compare null to the IPv4DefaultGateway. If it is null, we don’t want it. If it isn’t, then we want it. After that, we ask for the first result using the [0]. Most companies use the first network as the main network and the second network as a backup. That’s what we do at our company. Also most of the time the second network is a wifi network.

Next, we Ask for the IPv4Address and ask for just the IP address with .IPv4Address.IpAddress. Once we have all that information, we place it into a variable.

Now it’s time to start IE. You can set the browser to whatever program you like, but for now, we are still using IE for grandpa’s coded sites. We do this using the Start-Process command. We tell start-process the file path. This is where you can set google chrome, a 64 bit, edge, etc… It doesn’t matter what the browser is, as long as you point to one.

The Argument List is an important factor here. We give the site information here. We start off with our “https:// Then we do magic. We $($IP.address.split(‘.’)[0]. The act of using two $ is very important inside a double-quoted string. The reason why is we are stating everything inside $() is it’s own thing. We can run different commands inside $() and the output will output at that point in the string. Thus we are breaking the IP address string down by the . and finding each array point. Then after we create that point, we finish it off with a . and start our next $(). We do this until we reach our last octet. Which will be whatever the default IP address is. Finally finishing off with the site name. In this example, login.aspx. Below is the start process part of the command. Take a close look at the argument list. Assume the IP address is 10.10.1.15. This would start a site looking at “https://10.10.1.5/login.aspx”.

Start-Process -FilePath 'C:\Program Files\Internet Explorer\iexplore.exe' -ArgumentList "https://$($IPaddress.split('.')[0]).$($IPaddress.split('.')[1]).$($IPaddress.split('.')[2]).5/login.aspx"

The final step is to set your lnk to open the PowerShell script with a -bypass flag. This way it will execute. Some companies do not allow PowerShell to execute. In that case, this script does not help. You can however use the match version of this script found below.

@echo off
for /f "usebackq tokens=2 delims=:" %%f in (`ipconfig ^| findstr /c:"IPv4 Address"`) do set "ip=%%f"

for /f "tokens=1-4 delims=. " %%a in ("%ip%") do (
set octetA=%%a
set octetB=%%b
set octetC=%%c
set octetD=%%d
)

start "CMD" /D "C:\Windows\System32\" /max "C:\Program Files\Internet Explorer\iexplore.exe" "https://%octetA%.%octetB%.%octetC%.5/login.aspx"
exit

Conclusion

The final idea is to have the link to point to an organic system that can read the current IP structure and point the link to the correct page. This will allow that single roaming device to find those local sites quickly assuming you have a pre-planned infrastructure in place.

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