Networking problem

[Shane Dawalt]

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