No Name Resolution
 

New Sonya 18.2 install.

WiFi is connected, but Net names are not resolved to IP addresses! (e.g, Firefox, lynx, ping).

Nameserver shown is 127.0.1.1, just like the 17.3 I am posting this from. I don't have a clue how to solve this problem.

BTW, why the "odd" interface names? What happened to good old wlan0?

The is due to the move predictable network interface naming with systemd/udev. (It is possible to revert back to the traditional naming though if desired.)

https://www.freedesktop.org/wiki/Sof...nterfaceNames/

I'm not a Mint user, but IIRC Ubuntu/Linux Mint is using dnsmasq...
https://community.linuxmint.com/tutorial/view/489
https://wiki.debian.org/HowTo/dnsmasq

ferrari:

OK, that clears up the odd interface names. Thanks.

Alas, the references following were interesting, but didn't quite fit the details of my Mint installation. Both 'dhclient' and 'dnsmasq' seem to be started at bootup (or via initram) so I have no control over their startup parameters. Bottom line: I'm still stumped for a diagnosis and a fix.

Thanks again.

Are you using NwtworkManager to manage your network connections? Or the traditional way with interfaces defined in /etc/network/interfaces?

If using NetworkManager, some users have found that dnsmasq is problematic disabled it as described here...
https://mytechnicalthoughts.wordpres...linux-mint-18/

BTW, if you do that you'll also have to restart NetworkManager with
and the networking service can be restarted similarly with

ferrari:

The '#dns=dnsmasq' approach looks interesting. I was referred to another source for the same approach, as well as a 'how-to' on using static nameserver addresses; e.g.8.8.8.8

Even though no data can be sent or received, ifconfig and iwconfig shows that the WiFi is up:
Eventually the WiFi just goes down. And all at an unpredictable interval after boot! If '#dns=dnsmasq' etc can't fix this I'm going to have to give up on 18.2--too undependable.

Thanks for listening.

This reads like you have more than one issue at play. You mentioned
What do you mean that no data can be sent of received? If you can ping an internet address (by IP address) eg
then this implies that your internet gatway is working, and likely that only name resolution is not working eg
If only the latter fails, then it is a name resolution problem.

This is a different issue, and has nothing to do with DNS, but could well be due to power management. It needs to be investigated separately, but a good approach is to watch NetworkManager logging in a terminal window, and capture the event where the wifi drops out...

Worthwhile suggestions all!
IIR ping fails.
Alas, the return from sudo 'journalctl -fu NetworkManager' is "command not found."

I'll have a fresh look when I boot into 18.2 again.

I understood Linux Mint 18.2 is using systemd, so I'm surprised to read this.

If you can't even ping by IP address, then you should post the following when connected:
There should be a default gateway address (pointing at your router) - all generally assigned by DHCP.

I think I know the mistake you made - You typed this...
That won't work - hence the error that you got.

Enter it as I gave it in post #8 ie

I must have mistyped the journalctl command last time. When the connection drops, output from journalctl is like drinking from a firehose :-). Connection seems to be reestablished (after a delay) following . Then the journalctl command just waits after I disabled dnsmasq as suggested. I tried using a static /etc/resolv.conf, but NetworkManager still supplies its own DNS IP addresses. Things seem to work OK, but clearly my dropout problem isn't solved yet.

Your 'power management' comment led me to /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf! I'm going to set wifi.powersave = 3 to wifi.powersave = 0.

Again, sincere thanks for all your insights, and for staying with me on this.

Looks like this was indeed a power management problem. Here are the 3 changes I made that fixed things:

Stopped WiFi power management by changing "wifi.powersave = 3" to "wifi.powersave = 2" in
/etc/NetworkManager/conf.d/default-wifi-powersave-on.conf

Stopped dnsmasq by commenting out the line "dns = dnsmasq" in /etc/NetworkManager/NetworkManager.conf

Added static DN Servers by adding the line "prepend domain-name-servers 8.8.8.8, 8.8.4.4;"
to /etc/dhcp/dhclient.conf

Items 2 and 3 were probably not necessary.

Thanks again for all the suggestions, ideas, etc.