[SOLVED] No Name Resolution

notadoc · 11-26-2017, 02:07 PM

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?

ferrari · 11-26-2017, 02:44 PM

Quote:

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/

ferrari · 11-26-2017, 02:49 PM

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

notadoc · 11-27-2017, 12:49 PM

ferrari:

Quote:

The is due to the move predictable network interface naming with systemd/udev...

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

Alas, the references following

Quote:

I'm not a Mint user, but IIRC Ubuntu/Linux Mint is using dnsmasq...

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.

ferrari · 11-27-2017, 01:22 PM

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/

ferrari · 11-27-2017, 01:29 PM

BTW, if you do that you'll also have to restart NetworkManager with

Code:

sudo systemctl restart network-manager

and the networking service can be restarted similarly with

Code:

sudo systemctl restart networking

notadoc · 11-28-2017, 02:45 PM

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:

Quote:

wlp4s0 IEEE 802.11 ESSID:"XXXX"
Mode:Managed Frequency:2.437 GHz Access Point: XXXX
Bit Rate=12 Mb/s Tx-Power=30 dBm
Retry short limit:7 RTS thr

ff Fragment thr

ff
Power Management

n
Link Quality=60/70 Signal level=-50 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:1396 Invalid misc:168 Missed beacon:0

XXXX@name:~$ ifconfig wlp4s0
wlp4s0 Link encap:Ethernet HWaddr 00:08:a1:b4:f9:3b
inet addr:172.16.8.51 Bcast:172.16.15.255 Mask:255.255.240.0
inet6 addr: fe80::a988:4813:e53c:ad6a/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1127345 errors:0 dropped:0 overruns:0 frame:0
TX packets:530007 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:973092522 (973.0 MB) TX bytes:47144384 (47.1 MB)

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.

ferrari · 11-28-2017, 02:58 PM

This reads like you have more than one issue at play. You mentioned

Quote:

Even though no data can be sent or received, ifconfig and iwconfig shows that the WiFi is up:

What do you mean that no data can be sent of received? If you can ping an internet address (by IP address) eg

Code:

ping 8.8.8.8

then this implies that your internet gatway is working, and likely that only name resolution is not working eg

Code:

dig google.com

If only the latter fails, then it is a name resolution problem.

Quote:

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.

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...

Code:

sudo journalctl -fu NetworkManager

notadoc · 11-28-2017, 03:16 PM

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.

ferrari · 11-28-2017, 04:41 PM

Quote:

Alas, the return from sudo 'journalctl -fu NetworkManager' is "command not found."

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

ferrari · 11-28-2017, 04:43 PM

If you can't even ping by IP address, then you should post the following when connected:

Code:

ip address

Code:

ip route

There should be a default gateway address (pointing at your router) - all generally assigned by DHCP.

ferrari · 11-28-2017, 04:48 PM

Quote:

Alas, the return from sudo 'journalctl -fu NetworkManager' is "command not found."

I think I know the mistake you made - You typed this...

Code:

sudo 'journalctl -fu NetworkManager'

That won't work - hence the error that you got.

Enter it as I gave it in post #8 ie

Code:

sudo journalctl -fu NetworkManager

notadoc · 11-29-2017, 01:16 PM

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

Code:

sudo systemctl restart wpa_supplicant

. Then the journalctl command just waits after

Quote:

Activation: successful, device activated.

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.

notadoc · 12-01-2017, 12:53 PM

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.