Dummy IP address blocks all access to Nebulo if 8.8.8.8 is blocked in firewall.
I don't trust Google, for good reason... they've disregarded user settings disabling OTA updates and attempted to push a system update via GoogleOtaBinder, they've downloaded software without notification or permission, they've abruptly and without notification or permission rebooted the phone, borking an already-in-progress installation and rendering the phone unusable and necessitating a restore from a backup... all in an attempt at getting back permissions I'd retracted so they couldn't collect personal information and monetize it... not to mention the several instances of less than honest behavior I've found (ever look at your Advertising ID? It's fake... stored in /data/data/com.google.android.gms/shared_prefs/adid_settings.xml as "fake_adid_key"... the real Ad ID (under "adid_key") never changes no matter how many times you mash the button to reset your Advertising ID... which means Google's tracking you with a GUID... the fake_adid_key is like the fake "Close Door" button on an elevator... it really does nothing except make you think you're changing your Ad ID).
So in my AFWall+ firewall, I use the dot shell command to import iptables rules (I keep them on my computer, and have a script which updates them as needed via ADB) which blocks all of Google's CIDR ranges for the Default firewall profile. My 'Google-Enabled' profile is only used when checking for updates.
So when, after your Nebulo app gets notification that the network is up and you set a dummy IP address of 8.8.8.8, well... that's blocked in my firewall, inbound and outbound. So Nebulo never gets any traffic even after the IP address is updated with the private IP address of the network it's on.
I just confirmed this... I commented out in my Default firewall profile:
#$IP4 -A INPUT -s 8.8.8.8/32 -j REJECT
#$IP4 -A "afwall" -d 8.8.8.8/32 -j REJECT
And Nebulo started working.
Can we change the dummy IP to something not-Google, or give the user the interface component to set their own dummy IP?