Can connect to wifi but not to Internet with nm-applet.

Archy1 · 07-07-2015, 07:07 AM

I just installed Debian 8 amd64 on my laptop and when I go to nm-applet to connect to wifi and it connects just fine (I can ping my gateway) but I can't ping external IP address or resolve names.

After I run as root:

Code:

# dhcpclient wlan0
RTNETLINK answers: File exists

I can access the Internet and resolve names just fine but logging in as root and running "dhcpclient wlan0" every time I turn on the computer is getting annoying.

How can I avoid having to go through the whole "dhcpclient wlan0" mess every time?

cynwulf · 07-07-2015, 07:18 AM

I haven't used nm-applet (or network manager) for years. I assume you're using nm-applet because you're running a window manager? If so then how are you starting it?

ondoho · 07-08-2015, 05:05 AM

...and how did you install networkmanager?

could it be a permission issue?

could it be you have to disable all network-related systemctl/netctl-services before enabling networkmanager?

ferrari · 07-08-2015, 05:34 AM

Do you have a default route defined?

Code:

ip addr

Code:

ip route

Is your Network Manager connection configured as DHCP or using static addresses? (The configuration file located in /etc/NetworkManager/system-connections/ might us here.)

Archy1 · 07-11-2015, 10:56 AM

An update.

Apparently I can use the Internet just fine as long as I never switch to another tty (e.g. ctrl+alt+f6), once I switch to another tty (even if I don't log in) I have to run "dhcpclient wlan0" as root. However, after I run that I can switch ttys all I want and the Internet won't go out.

EDIT: I just found out that if I close my laptop lid shut, I have to redo "dhcpclient wlan0" to get Internet again (but once again it automatically connects to the LAN).

Quote:

Originally Posted by cynwulf

I assume you're using nm-applet because you're running a window manager? If so then how are you starting it?

Lightdm logs me into an LXDE on openbox session and nm-applet appears in the system tray, already connected to my router via wifi (and I can access the Internet until I switch ttys).

Quote:

Originally Posted by ondoho

...and how did you install networkmanager?

Code:

apt-get install network-manager network-manager-gnome

ip addr:

Code:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000
    link/ether xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
    inet 169.254.7.94/16 brd 169.254.255.255 scope link eth0:avahi
       valid_lft forever preferred_lft forever
3: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
    inet 192.168.1.14/24 brd 192.168.1.255 scope global dynamic wlan0
       valid_lft 85639sec preferred_lft 85639sec
    inet6 fe80::260a:64ff:feab:e5b9/64 scope link 
       valid_lft forever preferred_lft forever

ip route:

Code:

default via 192.168.1.1 dev wlan0 
default dev eth0  scope link  metric 1002 
default via 192.168.1.1 dev wlan0  proto static  metric 1024 
169.254.0.0/16 dev eth0  proto kernel  scope link  src 169.254.7.94 
169.254.0.0/16 dev wlan0  scope link  metric 1000 
192.168.1.0/24 dev wlan0  proto kernel  scope link  src 192.168.1.14

cat /etc/NetworkManager/system-connections/MY-SSID:

Code:

[connection]
id=MY-SSID
uuid=eb018dcc-4a3a-4377-954e-2d7ba9fab6d6
type=wifi
timestamp=1436267949

[wifi]
ssid=MY-SSID
mode=infrastructure
mac-address=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
security=802-11-wireless-security

[wifi-security]
key-mgmt=wpa-psk
psk=xxxxxxxxxxxxxxxxxxxxxxxxxxxxx

[ipv4]
method=auto

[ipv6]
method=auto
ip6-privacy=0

Note that I ran all these commands after I had gone to another tty and issues "dhcpclient wlan0" as root.

ferrari · 07-11-2015, 04:54 PM

Quote:

An update.

Apparently I can use the Internet just fine as long as I never switch to another tty (e.g. ctrl+alt+f6), once I switch to another tty (even if I don't log in) I have to run "dhcpclient wlan0" as root. However, after I run that I can switch ttys all I want and the Internet won't go out.

EDIT: I just found out that if I close my laptop lid shut, I have to redo "dhcpclient wlan0" to get Internet again (but once again it automatically connects to the LAN).

Your NM connection is defined as a system-wide connection (as opposed to user connection), so I would expect it to be available in other VT's. As ondoho suggested, have you stopped using other network services? Is the wlan0 interface excluded in /etc/network/interfaces?

So, just to check that the device is not unmanaged...

Code:

cat /etc/network/interfaces

Code:

nmcli dev status

Archy1 · 07-12-2015, 10:47 AM

Quote:

Originally Posted by ferrari

As ondoho suggested, have you stopped using other network services?

Sorry to display my ignorance but how would I do that?

Quote:

Is the wlan0 interface excluded in /etc/network/interfaces?

So, just to check that the device is not unmanaged...

Code:

$ cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
allow-hotplug eth0
iface eth0 inet dhcp

Code:

$ nmcli dev status
DEVICE  TYPE      STATE      CONNECTION 
wlan0   wifi      connected  MY-SSID   
eth0    ethernet  unmanaged  --         
lo      loopback  unmanaged  --

Should I add

Code:

# WLAN
auto wlan0
iface wlan0 inet dhcp

to "/etc/network/interfaces"?

ondoho · 07-12-2015, 12:35 PM

Quote:

Originally Posted by Archy1

Sorry to display my ignorance but how would I do that?

sorry i'm not using debian, but on my archlinux system i once had a rather similar problem, which turned out to be that there were conflicting services (now that debian is using systemd, too, there is more common ground) for dns resolving, iirc.
anyhow, for me something like

Code:

# systemctl stop dhcpcd.service
# systemctl disable dhcpcd.service

solved it.

and before & after you should always have a look with e.g.

Code:

systemctl status dhcpcd

btw, have you tried:

Code:

$ ping google.com
$ ping 8.8.8.8

if the latter is succesful, but not the former, that means you have a dns problem - you are connected to the internet, but domain names are not being resolved.

but in any case you should consult the debian wiki.
which i'm sure you have done before posting here.

ferrari · 07-12-2015, 01:44 PM

Quote:

Should I add
Code:

# WLAN
auto wlan0
iface wlan0 inet dhcp

to "/etc/network/interfaces"?

No, don't add the wlan0 interface to /etc/network/interfaces, otherwise NM will treat it as unmanaged (as with your wired ethernet interface).

When you switch VT, check the connectivity status again with

Code:

nmcli dev status

Maybe you still are connected. Do the ping tests that ondoho suggested as well in that VT.

Archy1 · 07-17-2015, 05:25 PM

Some more updates.

Changing VTs was a miss attributed cause. The Internet stops working after about 100 seconds of uptime. I just normally switch VTs quickly so I attributed it to that.

I created this Bourne script to test when the Internet goes out:

Code:

#!/bin/sh
counter=5
while [ $counter -gt 0 ]; do
    echo ""
    cat /proc/uptime | cut -c 1-3
    echo ""
    echo "google.com:"
    ping -q -c 1 google.com | grep loss
    sleep 1

    echo ""
    cat /proc/uptime | cut -c 1-3
    echo ""
    echo "8.8.8.8:"
    ping -q -c 1 8.8.8.8 | grep loss
    sleep 1

done

Here's the output:

Code:

60.

google.com:
1 packets transmitted, 1 received, 0% packet loss, time 0ms

61.

8.8.8.8:
1 packets transmitted, 1 received, 0% packet loss, time 0ms

62.

google.com:
1 packets transmitted, 1 received, 0% packet loss, time 0ms

63.

8.8.8.8:
1 packets transmitted, 1 received, 0% packet loss, time 0ms

64.

google.com:
1 packets transmitted, 1 received, 0% packet loss, time 0ms

## [Redundant output snipped]

96.

google.com:
1 packets transmitted, 1 received, 0% packet loss, time 0ms

97.

8.8.8.8:
1 packets transmitted, 1 received, 0% packet loss, time 0ms

98.

google.com:
1 packets transmitted, 0 received, +1 errors, 100% packet loss, time 0ms

103

8.8.8.8:
1 packets transmitted, 0 received, +1 errors, 100% packet loss, time 0ms

105

google.com:
## COMMENT: [CTRL-C entered]

So something either executes to stop Internet access around that time or finishes executing something to stop Internet access.

Before Internet loss:

Code:

$ systemctl status dhcpcd

● dhcpcd.service
   Loaded: not-found (Reason: No such file or directory)
   Active: inactive (dead)

$ nmcli dev status

DEVICE  TYPE      STATE      CONNECTION 
wlan0   wifi      connected  MY-SSID   
eth0    ethernet  unmanaged  --         
lo      loopback  unmanaged  --

The output is identical after Internet loss. Keep in mind that I can still access network resources on the LAN (like my router), yet I can not ping external address by IP so it looks like this is more than a DNS problem.

I didn't run the systemctl stop and disable commands as the status argument didn't find the service loaded.

ferrari · 07-17-2015, 07:40 PM

Quote:

Changing VTs was a miss attributed cause. The Internet stops working after about 100 seconds of uptime. I just normally switch VTs quickly so I attributed it to that.

As I suspected. A system-wide NM connection is exactly that.

Quote:

The output is identical after Internet loss. Keep in mind that I can still access network resources on the LAN (like my router), yet I can not ping external address by IP so it looks like this is more than a DNS problem.

So, your wifi connection remains associated. So, not a NetworkManager issue. Check if you still have a valid default route when that occurs and can still ping the router. If that checks out but you can't reach the internet then that would suggest a router issue.

ondoho · 07-29-2015, 01:45 PM

well it's a bit late now, but in addition to what has been suggested already:

i vaguely remember something about certain wifi cards having similar problems with encryption.
there was workarounds; but first, one way to troubleshoot is to temporarily completely disable encryption and see how that works.
that would be somewhat hardware/driver related and you should also check

Code:

dmesg

before and after connection loss.

anyhow with your newly gained insight, have you made further searches into your problem?

also the info requested here would be good, if you want further assistance.