Peter,

I was referring to Kirk's not seeing port 1502 after he assigned it in 
the loadusr statement, and how the OS handles ports above 1024.

Mark

On 02/29/2012 06:07 AM, Peter Homann wrote:
> Hi,
>
> Port 502 is assigned to Modbus, so that's what slaves should use by default.
>
> Cheers,
>
>
> Peter.
>
> On 29/02/2012 9:40 PM, Mark Wendt wrote:
>    
>> On 02/28/2012 05:21 PM, Kirk Wallace wrote:
>>      
>>> ... snip
>>>
>>> I think I know a little more now. I was able to bring up
>>> "loadusr classicladder --modslave" (I didn't know the rt component had
>>> to be loaded too). My netstat returned the same result above with
>>> "0.0.0.0:9502". I then did a ifconfig to find my network computer's
>>> addresses with 192.168.1.10 (eth0) and 127.0.0.0 (localhost) being
>>> listed. I nmap both addresses and found port 9502 open on both, so it
>>> seems by default, "--modslave" will listen on all addresses (two in this
>>> case), with "all or any addresses" being called out as "0.0.0.0".
>>> http://en.wikipedia.org/wiki/0.0.0.0
>>>
>>> If I use "loadusr classicladder --modslave --modbus_port=1502" netstat
>>> sees port 1502 as listening, nmap doesn't see it whereas it did see 9502
>>> previously. My guess is that as any ports above 1000 have lighter
>>> restrictions, maybe ports above a higher value are handled differently
>>> too, so 1502 doesn't show where 9502 does. I guess I have more work to
>>> do.
>>>
>>> I haven't tried connecting to the LinuxCNC slave with a master yet.
>>>
>>>        
>> Actually, ports 1024 and below are considered "privileged" ports.  Any
>> ports above that are considered "non-privileged" ports and are all
>> treated the same.  Do a 'netstat -a | grep 1502' and see if the 1502
>> port shows up.
>>
>> Mark
>>
>>
>> ------------------------------------------------------------------------------
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>>      
>    


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Virtualization & Cloud Management Using Capacity Planning
Cloud computing makes use of virtualization - but cloud computing 
also focuses on allowing computing to be delivered as a service.
http://www.accelacomm.com/jaw/sfnl/114/51521223/
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