I had this problem when I initially installed 7.5 and didn't think anything of it, but it happened again when I installed 7.6.
After reboot the system says that the wan interface is up and shows the external address to be the last routable address, but there is no connectivity. With 7.5 I had to reboot the device fully and reboot my modem in order to trick it into bringing up the interface properly. This time, after the update, I had to bring the interface down/up and force a refresh.
This makes applying updates very difficult as it leads to far longer periods of downtime than usual (with previous versions outages were a minute or two).
My Setup:
Astaro running on ESXi with wan virtual switch, to physical nic, directly connected to my cable modem.
This is the same setup i had with previous ASG and it never had any trouble bring the interface back up after update/reboot.
