I figured out the problem. The gateway addresses need to be empty. If you
delete the entry and create a new one you can use an empty gateway
address. If you have an address in the field, including 0.0.0.0, you
cannot save an empty gateway address.
On Tue, Oct 6, 2015 at 5:56 PM, linux guy <linuxguy123(a)gmail.com> wrote:
I need to connect a wifi device to my Linux computer. There is no
router
in between the two. Just my computer and the device. The device has a fixed
IP, 192.168.0.10. It has its own Wifi interface built in It isn't capable
of connecting to a router. It has a fixed IP address.
My home wifi network uses 192.168.1.x. It has a router. It works fine. My
computer connects to it via its built in wifi interface.
I have added a USB wifi interface (dongle) to my computer to connect to
the device. My computer displays the device properly in a network manager
scan. So the device is available for connections.
Next I edit the connection for the device in network manager. The SSID is
filled in from the scan. I select Ad-hoc mode. Band, Channel, etc. are all
automatic.
Next I edit wifi security. The device is open security wise, so I select
None.
Next I edit the IPV4 tab. Under connection method I select Manual.
The next fields are DNS server and Search Domains. In a point to point
connection, there will be no DNS server. I leave the boxes blank.
Next up is adding the static IP address, netmask and gateway.
I set the address of my interface to be 192.168.0.123, because it was
recommended by another user who connected with an Apple device. I set
netmask to 255.255.255.0.
The next thing to set is the gateway address. Here is where I get
confused. What is a gateway in the context of a peer to peer connection ?
I try to leave it blank, but it won't let me. So I put in 0.0.0.0. I
also tried the address of the interface (192.168.0.123) and the address of
the device (192.168.0.10)
Then there is a route field. I add a route for the ip address
192.168.0.10, using a netmask of 255.255.255.0 and again it asks for a
gateway. I tried 0.0.0.0, the device address and the interface address.
I don't touch any of the IPV6 settings because the device doesn't support
IPV6 addresses.
I save everything and connect to the device successfully.
I run "arp -a" and the device is found connected to the interface. Yippee
!
Pinging the device fails. Destination Host Unreachable.
When I ping the device and watch in wireshark I see an ARP broadcast
message "Who has 192.168.0.10 ? Tell 192.168.0.123". 192.168.0.123 is the
static IP for the interface. And that is as far as the process gets.
When I watch the other interface and do a ping to a local device, I see
the same ARP broadcast message, but also a reply message to it.
192.168.1.142 is at <device MAC> And then the process continues
successfully.
So what am I missing in the setup of my adhoc connection such that the OS
knows that a message sent to my device (192.168.0.10) gets routed through
the USB wifi interface, ie the ARP broadcast message gets a reply ?
Thanks.