forum.vdsworld.com

Rebel49 · Posted: Mon Aug 26, 2002 10:57 pm Post subject: SNMP possible?

I was wondering if anyone has any experience using VDS and perhaps VDSDLL to talk SNMP to a network device. Specifically, I would like to retrieve information from a remote temperature sensor. I have the OID,commmunity and port info and would like just to be able to get a reply from a "GET REQUEST" at this time. Trap handling is not important
yet.

Worship

Any hints or example code would be dynamite!!! Worship

thanks,eh!

rebel49

Mac · Posted: Tue Aug 27, 2002 12:22 am Post subject:

Well, here's a slightly different idea...

If the temperature software keeps a log file, you
could check those periodically. If not, you could
run a program at startup to do so on each machine.

I don't have SNMP experience, but I'm sure some of
these other guys do. Wink

Cheers, Mac Smile

Skit3000 · Posted: Tue Aug 27, 2002 8:18 am Post subject:

There is an IO function in Tommy's vdsdll 2.7...
Also, there is a function to control serial-ports in the vdsdll3 dll.

I think it's possible to make something with that.

Rebel49 · Posted: Sun Jan 12, 2003 11:37 pm Post subject: Is @CHR(0) the kiss of death

I revived this project after many months and
feel like I almost got it working!

The approach I tried was to use VDSIPP to send a UDP packet
that contained a SNMP frame containing the query for
the temperature. Everything works to the point
where I have to assemble a string (message) for the
query. The stumbling point is @CHR(0) which is a null
and is a part of the SNMP frame. VDS will assemble
the string but will only process it up to the point of the
NULL. I use a sniffer program to view the actual message
and its correct up to the @CHR(0) but then everything else
is truncated. Mad

Please consider the following code:

cnodnarb · Posted: Mon Jan 13, 2003 12:24 am Post subject:

Hi! I checked visual basic and it can't do this either....c++ might be able to. I got curious and looked some stuff up on MSDN and found this page.

http://msdn.microsoft.com/library/en-us/vbenlr98/html/vamscANSITable.asp

Characters 0-7 11,12, 14-31 and 127 don't appear to be supported in Windows...

NodNarb

Rebel49 · Posted: Mon Jan 13, 2003 2:15 am Post subject: Is @CHR(0) the kiss of death?

Thanks for your input!

But if you substitute @CHR(0) with @CHR(1) it works fine!!
Prints a strange character between "abc" and "def" but you get
a seven character string which you can work with!?!

Hmmmm........
Question

Tommy · Posted: Mon Jan 13, 2003 3:14 pm Post subject:

Indeed, VDS can not handle the NULL character directly while other Windows languages
such as Delphi, C and C++ can. That's why "hex code" was invented by the author of VDSINOUT
to allow the DLL to work with null characters, though none of the currently available socket DLLs
support hex code.

Rebel49 · Posted: Mon Jan 13, 2003 4:30 pm Post subject: @CHR(0) is the kiss of death!

That confirms my suspicions.. Sad

Curses! Foiled again! Mad

Anyway, I will have a look at VDSinout to see
what I can learn from it.

Thanks for this!

REB

Rebel49 · Posted: Fri Jan 17, 2003 2:05 am Post subject: and the answer is.......

Well my original post asked if SNMP (SIMPLE NETWORK MANAGEMENT PROTOCOL) was possible using VDS.
And I think I have covered enough turf to say definately
YES and NO. Or more correctly NO and YES.

NO because of the NULL transmission problem mentioned above prohibits
VDS and any existing externals from transmittting the desired data to the network.

YES because I found a work around. There is a wonderful FREE and simple program at www.snmpview.de that will do the network polling and log the results to a file. I then scan the the log file at regular intervals to obtain the data which I customize and filter with VDS. So , indirectly, it works quite well. I am now monitoring temperature environments at
several distant communication sites in my province.

So thanks to MAC for the suggestion to scan log files (BTW the native
device wasnt capable of logging). Worship

And to Tommy for that information on the NULL character. Worship

And also to Lutz Schulz , the author of SNMPVIEW. Worship

Anyboby interested in Network monitoring or device monitoring could approach it in a like manner, probably with good results.

REB

vdsalchemist · Posted: Fri Jan 17, 2003 1:39 pm Post subject:

Hi Rebel49,
Actually this is not really true. There is an External DLL that can transfer that NULL character. I just have not had time to build a SNMP example for the Gadget.dll.... But yes you can build character Arrays that have NULL characters in the array at different locations and read those characters out. I just don't think that there are any External DLL's that deal specifically with Network protocols that can handle these characters.

It is very possible to do every thing that you are trying to do with the Gadget.dll Wink