Networking problem

[James McKenzie]

On 5/14/11 8:42 PM, JD wrote:
> On 05/14/11 19:41, Kevin J. Cummings wrote:
>> On 05/14/2011 10:09 PM, JD wrote:
>>> On 05/14/11 18:45, James McKenzie wrote:
>>>> On 5/14/11 6:40 PM, JD wrote:
>>>>> On 05/14/11 18:24, Joe Zeff wrote:
>>>>>> On 05/14/2011 01:27 PM, JD wrote:
>>>>>>> I also brought the fedora firewall down, and retried to ping Fedora
>>>>>>> from Powerbook. No go!!
>>>>>> That means that it's not a firewall issue.  Check your router config to
>>>>>> see if it's set to allow pings inside the LAN.
>>>>> Thanx!
>>>>> I checked. The gateway has a built-in feature (program)
>>>>> to let you ping any client on the lan (or any ip on the public net).
>>>>> The gateway can ping both the powerbook and the fedora pc.
>>>>> no problems there.
>>>>> The fedora pc and the powerbook can ping the gw, and a third machine
>>>>> connected to the GW by ethernet, and can of course ping addresses
>>>>> on the public net.
>>>>> They (fedora pc and powerbook) cannot ping each other!
>>>>> Powerbook firewall is set to promiscuous mode.
>>>>> And as I had stated earlier, I even stopped iptables on the
>>>>> fedora pc, which puts it also in promiscuous mode (I assume).
>>>>> Still these two machines refuse to talk.
>>>>>
>>>> Can you use traceroute to communicate between the two of them?
>>>>
>>>> James McKenzie
>>>>
>>> Tried it.
>>> Tracerout is unable to get to target after 30 tries.
>>> All it shows is asterisks.
>> Sounds to me like traceroute is trying to go "direct" between machines....
>>
>> 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.
>
That default route will ONLY be used if you specified the IP range as 
/32, i.e. 192.168.1.1/32.  Otherwise the system will assume /24 and 
nothing local will be able to be located (you should be able to ping 
outbound the gateway, but nothing else in that subnet.)

James McKenzie