# The Setup:
 - Raspberry Pi 3 B (*Raspbian GNU/Linux 9 (stretch)*) and boots to Command Line
 - (internal Wifi NIC) [**wlan0**]
 - additional external Wifi NIC [**wlan1**]

# What I want to achieve:
I Have two different wireless networks: One is always available (**a**), the other one not (**b**). I want to configure the networking in a way, that:

    wlan0 -> a
    wlan1 -> b
and the following happens but should not:

    wlan0 -> a
    wlan1 -> a
    ----or----
    wlan0 -> b
    wlan1 -> b

How do I avoid this?

# What have i done so far?
**Try1 (wpa_supplicant.conf & /etc/network/interfaces)**

    pi@raspi:~ $ cat /etc/wpa_supplicant/wpa_supplicant.conf
    ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
    update_config=1
    country=DE
    
    network={
            ssid="HomeNetwork"
            psk="############"
            id_str="home"
    }
    
    network={
            ssid="MobileNetwork"
            psk="############"
            id_str="mobile"
    }
    pi@raspi:~ $ cat /etc/network/interfaces
    auto lo
    
    iface lo inet loopback
    iface eth0 inet dhcp

    allow-hotplug wlan0
    iface wlan0 inet manual
    wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
    
    iface mobile inet dhcp

    allow-hotplug wlan1
    iface wlan1 inet manual
    wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf

    iface home inet dhcp

**Try2**

I've booted to Desktop and connected the interfaces to the according network and rebooted to Command Line...