This is the real ip and the only ip address that is known to the device.
If you want the external ip address then you need to use a web service that will return it.
Example:
B4X:
Sub GetExternalIp As ResumableSub
Dim j As HttpJob
j.Initialize("", Me)
j.Download("https://www.myexternalip.com/raw")
Wait For (j) JobDone(j As HttpJob)
Dim res As String = ""
If j.Success Then
res = j.GetString
End If
j.Release
Return res
End Sub