Re: CWBPING ( PING by port # ) in a CL program

Dear Jorge,

A few years ago, I was trying to assist a customer who
was running some software on their PC, which looked
like an IPDS capable printer to their IBM host. 

As it happened, the business process dictated that the
PC in question had to be powered off every evening.
Thus the customer wanted to code a CL routine on their
IBM host to ping the IP Address of the PC each morning
to find out when it had been powered on and to then
automatically start the IBM host based print writer
servicing the software running on the PC.

I asked Rodney Johnson, AS/400 Spool Technical team
lead who answers questions like this from users in the
comp.sys.ibm.as400.misc usenet newsgroup, whether he
might have any suggestions.

Here is some of the information he sent back to me,
that could be relevant to your requirement:

"The list joblog message API could be used to retrieve
the messages TCP3215 PING reply 1 from x.x.xxx.xxx
took 8 ms. 256 bytes. TTL or TCP3206 No response from
host within 1 seconds for connection from the joblog
after issueing the PING command.  Depending upon which
message ids were found would depend upon which action
should be taken.  I would use the API such that you
start with the last message issued and work your way
back.  We've got this type of think in OS code."

I also asked one of the developers I knew from the
days when I participated in the IETF TN3270E Working
Group (the group sponsored the TN5250E RFC as well)
what they would suggest. Their idea was as follows:

"Hello Paul,

I did a little digging into your request, and I think
there might be other ways to do what you want. 
However, if using ping from CL is your objective,
there are some features in the iSeries PING command
that will change how the caller is notified of success
or failure.  Have a look at the MSGMODE parameter for
PING, you can set it to kick back an *ESCAPE message
if the ping fails.  I'm thinking this is just what you
were looking for...

Of course, you realize that just because PING works,
it doesn't necessarily mean various TCP applications
are running....only that the TCP stack is alive.  In
the case of IPDS netwrok printers, I'm assuming the
stack only serves the print function so you can
probably assume the print function is running if the
stack pings successfully.

Hope this helps.
Jeff

Jeffrey Stevens
TCP/IP Applications & iSeries Connect"

I hope one of these ideas might be useful to your
requirement.

Best Regards,

/Paul
--
Paul Tykodi
Principal Consultant
TCS - Tykodi Consulting Services LLC
E-mail: ptykodi@xxxxxxxxxx

>date: Fri, 29 Apr 2005 16:17:40 -0400
>from: jmoreno@xxxxxxxxxxxxxxxx
>subject: CWBPING ( PING by  port # ) in a CL program 
 
>
>Hello all,
>
>We need to run a chewck on specific port numbers
every >so often.
>
>The Client Access - CWBPING facility will do this for
>us at V5R3
>
>From the "Windows Command Prompt" we can run the
>command . . . :CWBPING servername /port:# ] and we
>just look at the results
>
>However the requirement is to run as part of a CL
>program, to run in batch and to be able to read the
>"message results"
>
>- - - - - - -
>
>As a side note 
>
>In the past we have used the TCP/IP API
QtocLstNetCnn,  >NCNN0100 Format But we discovered
that the information >pertaining to the TCP/IP state
is not reliable. If the >API tells me that it is
listening, this does not >guarantee a connection
>
>------- 
>
>Your comments will be greatly appreciated 
>
>Jorge Moreno
>Overseas Military Car Sales
>Woodbury, New York


                
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