Networking problem

[JD]

On 05/14/11 21:28, Shane Dawalt wrote:
> On 05/15/2011 12:18 AM, JD wrote:
>> On 05/14/11 20:59, Kevin J. Cummings wrote:
>>> On 05/14/2011 11:42 PM, JD wrote:
>>>>> Can you add a "special" static route between the 2 specifying the router
>>>>> as the gateway?
>>>>>
>>>>> As I recall, LAN traffic assumes that anything sent on the local
>>>>> interface will get directly to anything else on the local network by
>>>>> just sending it.  I'm not sure why the router doesn't "route" those
>>>>> packets when it sees them unless it assumes that if receives them over
>>>>> the wireless and the target machine is also wireless, that that would be
>>>>> redundant.
>>>>>
>>>>> Sometimes I used to set up static routes between machines, guaranteeing
>>>>> that the route the packets take will get there.  something like:
>>>>>
>>>>> On machine w.x.y.2, sending to machine w.x.y.3, using the router at
>>>>> w.x.y.1 as the intermediary:
>>>>>
>>>>> # route add -host w.x.y.3 gw w.x.y.1 dev eth0
>>>>>
>>>>> I'm not 100% sure this will work, because if the router is at fault, it
>>>>> may still fail.  But its worth a try.
>>>>>
>>>> No that would not do anything because already the default route is
>>>> 192.168.1.254
>>>> which is the gateway/router.
>>> No.  The default route is only used when there is not a route found for
>>> the target machine.  If the target machine is on the same subnet, then
>>> the packets just get sent out on the local network device.  While its
>>> true that both the target machine and the router are on this network,
>>> this is the configuration that is not working for you.  What you want is
>>> to either add a specific route "before" the local network route so that
>>> all traffic to that machine gets sent to the router, or, remove your
>>> local network route from your routing table.  In that case, all you
>>> should have is a default route (that might work).
>>>
>>> This is my laptop routing table:
>>>> # route
>>>> Kernel IP routing table
>>>> Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
>>>> local.net       *               255.255.255.0   U     2      0        0 eth1
>>>> default         192.168.6.1     0.0.0.0         UG    0      0        0 eth1
>>> Note that any traffic to my local network gets put on the local network.
>>>     (This is the first routing line.)  BTW, local.net is 192.168.6.0/24.
>>>
>>> If there is traffic for *anywhere* else, that's what invokes the default
>>> route, and that gets sent to my router.
>>>
>>> I'm suggesting that you either have:
>>>
>>> 192.168.1.108	192.168.1.254	255.255.255.0	UG	wlan0
>>> 192.168.1.0	*		255.255.255.0	U	wlan0
>>> 0.0.0.0		192.168.1.254	0.0.0.0		UG	wlan0
>>>
>>> or you have only:
>>>
>>> 0.0.0.0		192.168.1.254	0.0.0.0		UG	wlan0
>>>
>>> I think you'll see a difference....
>>>
>>> I'm also wondering if you'll have to do the something similar on the
>>> "other" wireless machine.... (192.168.1.108?)  I'm assuming your 2
>>> "wireless" machines are 192.168.1.60&    192.168.1.108, and that your
>>> router is 192.168.1.254.
>>>
>> I do not seem to be able to alter the routing table.
>> Current table on Fedora pc is:
>> $ route -vn
>> 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
>> 0.0.0.0         192.168.1.254   0.0.0.0         UG    0      0        0
>> wlan0
>>
>> I removed interfaces eth0 and virbr0 (i.e. I deactivated them) so they
>> no longer
>> get configured at bootup.
>>
>     It simply cannot be a default route issue.  The OP is attempting to
> ping a device on the 192.168.1.0 network from a device on the
> 192.168.1.0 network.  They are local.  No router will get involved with
> this communication.  The machines themselves will not use their default
> route.  They will use 802.3 layer-2 communications to talk with one
> another, i.e., MAC addresses.   The traffic should be bridged/switched.
>
>     Shane
>
>
Well, that bridge is the router.
Wireless clients that are associated with an Access Point
in "infrastructure" mode cannot directly talk to each other.
Their traffic must  flow through the router.
If I had set the two computers to use AdHoc mode of
"association" with each other, then indeed, their traffic
would go directly to each other without any other facility
in between.