Where are the wifi error messages?

Question

I am using a standard Ubuntu 14.04 installation. When I try to connect to a certain router from the menu of routers in range, connection fails, and there is no error message.

Where do I find the error messages, if they exist?

Answer 1

You can find error messages in syslog:

cat /var/log/syslog

You can narrow down the lengthy log with grep:

cat /var/log/syslog | grep Network

...to see what Network Manager is doing

cat /var/log/syslog | grep wlan0

...assuming that wlan0 is your wireless interface. Find out with:

iwconfig

And also:

cat /var/log/syslog | grep <wireless_driver>

Substitute your wireless driver here. Find your wireless driver with:

sudo lshw -C network

Here is an example from my machine:

*-network
   description: Wireless interface
   product: Wireless 7260
   vendor: Intel Corporation
   physical id: 0
   bus info: pci@0000:03:00.0
   logical name: wlp3s0
   version: 6b
   serial: xx:3d:82:7a:fe:xx
   width: 64 bits
   clock: 33MHz
   capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
   configuration: broadcast=yes driver=iwlwifi driverversion=4.4.6-040406-generic firmware=17.265642.0 ip=192.168.0.125 latency=0 link=yes multicast=yes wireless=IEEE 802.11bgn
   resources: irq:31 memory:e0400000-e0401fff

Finally, from time to time, the log is archived and a new log begun. If the output from these commands is sparse, look at the archived log for more complete details:

cat /var/log/syslog.1 | grep Network

Answer 2

if you are using iwlwifi as driver. you may try, dmesg | grep iwlwifi

or just type dmesg on terminal and look for error that related to

wifi networking fail to connect