Regarding SNMPv1/SNMPv2c/SNMPv3 and the Modtronix SBC65EC/SBC66EC:
The Modtronix SBC65EC is based on the Microchip TCP/IP stack v3.75 (2006-08-14), and a PIC18 MCU. The Modtronix SBC66EC introduced last month (2011-03) is based on the Microchip TCP/IP stack v5.31 (2010-10-19, 14 significant revisions later!) and a PIC24 MCU.
To learn about the differences among SNMPv1, SNMPv2c, and SNMPv3, see http://en.wikipedia.org/wiki/SNMP
To learn about SNMP support in each version of the Microchip TCP/IP stack, download the latest Microchip Application Libraries (2010-10-19, 2000+ files) fromhttp://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=2680&dDocName=en547784
and see file "TCPIP Stack Version.txt". There might be easier ways to get this file, but that is how I found it. It is about 80 pages of ASCII text with well-written summaries of each release. Searching for "SNMP" shows its development by Microchip from 2002 to present. A comment in v3.75 notes says "SNMP, TFTPc modules have not been tested with this version." The same comment appears in v3.60 (2006-07-12), v3.50 (2006-04-13), v3.16.00 (2006-03-06), and that's as far back as I looked.
Microchip published Application Note (AN) 870a "An SNMP Agent for the Microchip TCP/IP Stack" (42 pages) in 2003. They updated it to AN870b "SNMP V2c Agent for the Microchip TCP/IP Stack" (40 pages) in 2009. That version is available athttp://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en012108
I am interested in SNMPv3, because of its security enhancements over SNMPv1 and SNMPv2c. The following paragraph is taken from "TCPIP Stack Version.txt", notes for Microchip TCP/IP Stack v5.31 (2010-10-19):
"16. Added preliminary SNMPv3 module. This module, enabled with the STACK_USE_SNMPV3_SERVER option in TCPIPConfig.h, implements the Simple Network Management Protocol, version 3. Among other things, SNMPv3 adds secure authentication and cryptographic privacy as compared to SNMPv2C. This implementation currently only supports AES encryption (no DES support). It also has only been tested with the PIC32 Ethernet Starter Kit (TCPIP Demo App - C32 - PIC32_ENET_SK_DM320004_INTERNAL_ETHERNET.mcp MPLAB IDE project). SNMPv3 on PIC18, PIC24, and dsPIC platforms are not supported at this time. Because AES encryption has specialized United States export requirements, this TCP/IP Stack release does not include the required AES library to enable SNMPv3. To obtain the needed AES library, you must purchase SW300052 v2.6 or later. Older v2.5 and previous versions include AES related files on them, but do not include the new AES files required by SNMPv3. For more information on using SNMP, refer to the TCP/IP Stack Help (Demo Information -> Available Demos -> TCPIP Demo App -> Demo Modules -> Network Management (SNMP) Server)."
Notice PIC18 (Modtronix SBC65EC) and PIC24 (Modtronix SBC66EC) are "not supported at this time" for SNMPv3, while PIC32 (used on the Microchip "PIC32 Ethernet Kit" hardware) is. SNMPv3 is "preliminary", even in this most recent release.
On the SBC65EC, I think SNMPv1 is possible but needs more investigation. Microchip published AN870a in 2003, and released their TCP/IP Stack v3.75 in 2006, that Modtronix uses in the SBC65EC. But the Microchip TCP/IP Stack revision history shows that although SNMPv1 likely worked in 2003, it went untested through several TCP/IP Stack revisions through the v3.75 (2006-08-14) release. Others in this forum have said that trying to compile it fails. I haven't tried getting it to work. AN870a would be the key to getting this to work. I don't think SNMPv2c or SNMPv3 will work on the SBC65EC, because Microchip published AN870b, advertising SNMPv2c, in 2009, 3 years after the TCP/IP stack version used in the SBC65EC. If Modtronix were to update the SBC65EC Web Server from Microchip TCP/IP Stack v3.75 to v5.31 (a 14-revision jump and maybe not even possible), then I think the SBC65EC would cleanly support either SNMPv1 or SNMPv2c.
On the SBC66EC, I think SNMPv1 and SNMPv2c should both work as described in Microchip AN870b. But I don't think SNMPv3 will work, because (in the note above) "SNMPv3 on PIC18, PIC24, and dsPIC platforms are not supported at this time." "This time" is 2010-10-19, Microchip TCP/IP stack v5.31, the most current version today, as used in the SBC66EC.
If you want SNMPv3 as I do, I think neither the Modtronix SBC65EC or SBC66EC will work because Microchip's SNMPv3 currently only works on PIC32 MCUs, not PIC24 (SBC66EC) or PIC18 (SBC65EC).