My OS: OS in question, and my primary OS: Debian 9.1 (fresh install) with i3 window manager (no DE). Other OSes (dual booted): Ubuntu 14.04 and Windows 10.
Kernel: 4.9.0-3-amd64
Network cards info: Realtek 8101 ethernet controller which works out-of-the-box (verified many times in Debian 9, Ubuntu, ...) and a Realtek 8723be Wireless network adapter which needs additional tweaking (Installation of a driver patch - due to a fault in the default drivers - tried by myself, it worked fine.).
I installed network-manager-gnome to manage my networks (although ethernet is unmanaged by it since eno1 (my ethernet) appears in /etc/networks/interfaces)
Problem: Network (neither ethernet nor WiFi) doesn't work on fresh reboot. By this I mean that - if I directly boot into Debian and try accessing the internet, it doesn't work. But, if I first boot into say, my Ubuntu, login to the internet there (see Additional info 1 below) and come back to Debian, it works! I have tried this a lot of times and the pattern is always that.
Additional info 1: I am accessing internet from a university campus, so there's a network login page that I must first visit and login. I can't open this login page upon a fresh restart, but if I already login and come to Debian, I can! I find this very strange.
EDIT: There's no proxy server involved. Just a login page.
Additional info 2: There's a known kernel-panic bug associated with my particular Wireless network adapter, network-manager-gnome and Debian. I experienced it as follows: If I don't install that said driver patch for my Wireless adapter, I experience kernel-panic during bootup (sometimes multiple times) and if I do install it, there's no kernel-panic.
To confirm this is indeed the reason for kernel-panic, I checked the syslog at /var/log/syslog and observed something on the lines of wlo1... just prior to the kernel-panic entry.
And please note, with that driver patch I can use my Wireless adapter perfectly fine (provided I login to internet in my Ubuntu for a and come back!).
My question: Why does my network show such a strange pattern, how do I correct it? Any leads would be appreciated. Thanks a lot!
dmesgoutput after boot of both distros to verify this guess.