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I finally managed to make wlan0 (an Edimax EW-7811Un USB WiFi dongle) connect to my router, but after an apt-get update I discovered that my Raspberry can't connect outside the local network. The Raspberry is running on the latest (as of writing this) Raspbian image.

  • wlan0 is connected to my router and has been given an IP address
  • I can ping my router, my printer, and other machines inside the local network, but I can't ping anything in the outside net (also loopback ping on localhost says "host unreachable", but I'd say that it is NAT cancelling 127.0.0.1 requests)
  • I can successfully connect through eth0, but I need to connect through wlan0.

ifconfig output:

pi@MinoPi ~ $ ifconfig wlan0
wlan0     Link encap:Ethernet  HWaddr *macaddresshere*
      inet addr:192.168.1.9  Bcast:192.168.1.255  Mask:255.255.255.0
      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
      RX packets:552 errors:0 dropped:6 overruns:0 frame:0
      TX packets:289 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1000
      RX bytes:375003 (366.2 KiB)  TX bytes:318051 (310.5 KiB)

iwconfig output:

pi@MinoPi ~ $ iwconfig wlan0
wlan0     IEEE 802.11bg  ESSID:"Sanctuary"  Nickname:"<WIFI@REALTEK>"
      Mode:Managed  Frequency:2.437 GHz  Access Point: *macaddresshere*
      Bit Rate:54 Mb/s   Sensitivity:0/0
      Retry:off   RTS thr:off   Fragment thr:off
      Power Management:off
      Link Quality=100/100  Signal level=100/100  Noise level=0/100
      Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
      Tx excessive retries:0  Invalid misc:0   Missed beacon:0

/etc/network/interfaces file:

auto lo

iface lo inet loopback
iface eth0 inet dhcp


iface wlan0 inet static
    address 192.168.1.9
    netmask 255.255.255.0
    gateway 192.168.1.1
    wpa-ssid "Sanctuary"
    wpa-psk "somePasswordHere"

Any ideas?

Błażej Michalik
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1 Answers1

73

Problem solved! It seems that even though I added the gateway information into the interfaces file, wlan0 didn't really have a default gateway.

When I ran

sudo route -n

it yielded

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 wlan0

There it is - no Gateway IP. I typed this:

 sudo route add default gw 192.168.1.1

(where 192.168.1.1 is an IP address of my router, which is connected to the outside net)

Et voilà: it works.

Błażej Michalik
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    Anyone got any clue as to why the gateway isn't being added automatically? – Endareth Jan 05 '16 at 03:47
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    @Błażej Michalik, I am using Raspberry PI 3 operating system. The problem is in masking the gateway Ip address and * persisting it * across reboots. How would you propose to maskthe gateway Ip address and * persist it * across reboots? Thanks – Frank Aug 19 '16 at 14:31
  • @Frank Gateway IP is not masked, it is just an address, it's not a range of addresses. You have to add a gateway route to your routing tables. The masking of destination addresses is up to your local network setting. The route utility should add the address in a persistent way, but I think it is depreciated now, you can look up ip route (man ip). – Błażej Michalik Aug 20 '16 at 15:50
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    I am very much interested in the answer to @Endareth question - even more so in how to code a response for the raspberry pi to find and connect to a response automatically. If you give a raspberry pi as a gift to someone who doesn't know computers, it shouldn't stop operating immediately. – chase Mar 24 '17 at 17:36