KDE: DNS problems, orange exclamation mark on systray icon
Since upgrading to Fedora 22, I've intermittentaly had DNS problems, and when this occurs there's always an orange exclamation mark on the KDE/Plasma networking system tray icon. Using the icon's popup menu to display more details for the connection gives no insights. Grepping /var/log/messages for DNS shows nothing interesting. chrome and ping report it as a timeout, while dig reports it as not being able to find any DNS servers. ping -n and mtr -n have no problem reaching the two nameservers listed in /etc/resolve/conf, so I don't know why there's this problem.
My Linux machine uses a wireless connection. A Windows 7 machine which is directly/non-wirelessly connected to the XFinity wireless router (and which uses the same nameservers as my Linux machine) can use DNS, but while the Linux DNS problem persists the Windows name lookups seem to take longer than normal, and Chrome intermittently gives DNS errors like DNS_PROBE_FINISHED_BAD_CONFIG, DNS_PROBE_FINISHED_NXDOMAIN and DNS_PROBE_STARTED.
I've tried the following solutions, all to no avail:
- Use the systray icon network popup menu to disconnect and reconnect to the wireless router.
- Use
/etc/rc.d/init.d/networkto stop and restart networking. - Removing and reinsterting the USB wireless network device.
- Disabling the firewall.
- Restarting the avahi demon.
- Editing
/etc/nsswitch.confto skip mDNS and go directly to DNS. - Rebooting the computer.
- Doing a soft-reset of the XFinity wireless router.
Two questions. First, is your Fedora box using the same DNS servers as your Windows box? Second, can you ping 23.202.254.127? (It's a site I use that I know responds properly to pings.) If you can reach out and ping by IP, it's not a connectivity or routing issue; if you can't, try using traceroute.
1) They both use the same nameservers 2) the problem is gone for the moment, so I can't test if there's a routing problem