Short summary (added after the problem was solved)
Apparently some wireless USB network adapter drivers were incompatible with my Linux OS, and in the end I worked around the problem by buying a wireless bridge ~= receiver ~= wireless access point. Now, here is the actual question:
Question:
If a computer has been provided an IP address by a broadband router, and the firewall is turned off, but internet nevertheless doesn't work and it's not even possible to ping the router, then what might the problem be? And how can I fix it?
Background:
I'm unable to connect from my desktop to [the wireless broadband router in the
appartment to which I've just moved], via [a wireless network USB card].
The router gives me an IP address (first it asks me to specify a WSP PIN code, which I do), but although I get an IP address, I'm unable to reach the Internet: I cannot resove any host names, and I cannot even ping the broadband router, i.e. the machine that gave me the IP address (!).
More information:
Below follows lots of hopefully helpful information.
My laptop, which has always been configured via DHCP, is able to connect to
the broadband router without any issues. Only
my desktop doesn't work. It recently had bridged networking configured.
Here are my desktop's interfaces, after I've connected it to the broadband router. wlan0 (at the end of the list) is the network USB card.
$ ip ad
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
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 qlen 1000
link/ether 20:cf:30:4c:2f:02 brd ff:ff:ff:ff:ff:ff
inet6 fe80::22cf:30ff:fe4c:2f02/64 scope link
valid_lft forever preferred_lft forever
(Uninteresting stuff related to KVM, VMWare, VirtualBox:
4: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN
link/ether 6e:84:3c:57:95:4a brd ff:ff:ff:ff:ff:ff
inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
5: vmnet1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000
link/ether 00:50:56:c0:00:01 brd ff:ff:ff:ff:ff:ff
inet 172.16.228.1/24 brd 172.16.228.255 scope global vmnet1
inet6 fe80::250:56ff:fec0:1/64 scope link
valid_lft forever preferred_lft forever
6: vmnet8: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000
link/ether 00:50:56:c0:00:08 brd ff:ff:ff:ff:ff:ff
inet 192.168.133.1/24 brd 192.168.133.255 scope global vmnet8
inet6 fe80::250:56ff:fec0:8/64 scope link
valid_lft forever preferred_lft forever
END uninteresting stuff)
9: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000
link/ether 44:94:fc:29:59:6e brd ff:ff:ff:ff:ff:ff
inet 192.168.100.6/24 brd 192.168.100.255 scope global wlan0 <-- it has an IP addr (!)
inet6 fe80::4694:fcff:fe29:596e/64 scope link
valid_lft forever preferred_lft forever
Here is the routing table: (192.168.100.* is the broadband router's network)
$ route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default 192.168.100.1 0.0.0.0 UG 0 0 0 wlan0
link-local * 255.255.0.0 U 1000 0 0 wlan0
172.16.228.0 * 255.255.255.0 U 0 0 0 vmnet1
192.168.100.0 * 255.255.255.0 U 2 0 0 wlan0
192.168.122.0 * 255.255.255.0 U 0 0 0 virbr0
192.168.133.0 * 255.255.255.0 U 0 0 0 vmnet8
Here is the iptables configuration: (it's disabled, right?)
$ sudo iptables -nL
Chain INPUT (policy ACCEPT)
target prot opt source destination
Chain FORWARD (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
When I ping the gateway (192.168.100.1), and Google, ping says:
$ ping 192.168.100.1
PING 192.168.100.1 (192.168.100.1) 56(84) bytes of data.
From 192.168.100.6 icmp_seq=3 Destination Host Unreachable
From 192.168.100.6 icmp_seq=5 Destination Host Unreachable
From 192.168.100.6 icmp_seq=6 Destination Host Unreachable
$ ping google.com
ping: unknown host google.com
How is that possible? 192.168.100.1 has given me an IP address, then it cannot
be "unreachable"? I'm able to ping the gateway from my laptop, so it does
reply to ping requests.
Here is resolv.conf: (Why does it specify localhost???? — I suppose that's (parts of) the reason Google isn't ping:able?)
$ cat /etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 127.0.0.1
In the past, I had a bridged network configured in /etc/network/interfaces,
but I've commented it out, and restarted the whole computer. Here are the
not-commented-out lines in that file:
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet dhcp
I'm using Kubuntu 12.04 LTS. Network Manager shows wlan0 as status CONNECTED.
Update: Here's the output from lsusb:
$ lsusb
Bus 004 Device 004: ID 05f3:0081 PI Engineering, Inc. Kinesis Integrated Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 008 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 009 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 005 Device 002: ID 09da:0006 A4 Tech Co., Ltd Optical Mouse WOP-35 / Trust 450L Optical Mouse
Bus 004 Device 005: ID 05f3:0007 PI Engineering, Inc. Kinesis Advantage PRO MPC/USB Keyboard
Bus 002 Device 004: ID 0846:9021 NetGear, Inc.
Here's output for lsusb -v but for the NetGear device only: (for all devices, lsusb -v said "Couldn't open device, some information will be missing")
Bus 002 Device 004: ID 0846:9021 NetGear, Inc.
Couldn't open device, some information will be missing
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x0846 NetGear, Inc.
idProduct 0x9021
bcdDevice 2.00
iManufacturer 1
iProduct 2
iSerial 3
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 46
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0x80
(Bus Powered)
MaxPower 500mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 4
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 255 Vendor Specific Subclass
bInterfaceProtocol 255 Vendor Specific Protocol
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x03 EP 3 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x84 EP 4 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 1
