Help needed from somebody with the better networking knowledge than mine. Debian Buster on Dell M4800 Mobile Workstation, Intel Corporation Wireless 7260 (rev bb) WiFi adapter. The ISP modem offers 2 WiFi bands: 2.4G & 5G. The system connects automatically to 5G. 2.4G is reserved for my printer use. Email client - Evolution 3.30.5-1.1.
Starting of May 1, after system upgrade (dnsutils, bind9-host, and a bunch of related libs) I started having problems accessing GMail and Hotmail servers. Evolution ultimately connects and retrieves my mail but it take it from 20 up to 50 minutes. However, if I switch manually to 2.4G band or if I wire the laptop to the modem, Evolution connects on fly with no time. Reinstalling suspected upgrade did not help. My ISP replaced the modem with one with a newer firmware - no results I finally noticed that when on 5G band my IPv6 address cannot be detected by any of "what is my IP websites". Only IPv4 is visible to the outside world. But when I switch to 2.4 band (or wire the laptop to the modem) my IPv6 address is correctly detected along with the IPv4 one. CLI utilities confirm that my IPv6 is enabled and that WiFi interface is assigned an IPv6 address. One for 2.4G band & a different one for 5G band. I'm pushing my ISP to investigate their part of the network. But what bothers me is that I'm not sure in it. What if either Intel adapter or its Linux driver is in fault. And I have no means to test that... Any suggestions folks?..
