Tools for Network Management course project

SNMP Ping and Verify program

These two programs are simplified SNMP agent and manager (client). They can help to debug your course project.
SnmpPing generates an UDP packet with an SNMP get-request asking for sysDescr. SnmpVerify checks the received SNMP get-request PDU and replies a get-response PDU.

MSWindows (98/NT): SnmpVerify.exe, SnmpPing.exe.
Solaris 2.6 on SUN Sparc: SnmpVerify.sol, SnmpPing.sol.
Linux 2.2 Kernel on i386: SnmpVerify.lin, SnmpPing.lin.

Written by Jim Durrell <JimD@CoManage.net>, ported by Yu Liu <yuliu@sis.pitt.edu>

Notes:

I got some reports that following SNMP agents are not accessable from the clients out of pitt.edu(136.142.0.0/16). Now the problem has been fixed. To check this, use above SnmpPing to test your connections:

SnmpPing 136.142.117.51 public

Three SNMP agents running on port 161 in Telelabs are:

 136.142.117.51, fuchsia.tele.pitt.edu;
 136.142.117.54, milkweed.tele.pitt.edu;
 136.142.117.90;

Under Windows 2000, you can install an SNMP agent for PC. It is an add-on components under Management and Monitoring Tools in the Windows 2000 CDROM.

MG-Soft has evaluation version SNMP software which might help your debuging. The other helpful website is here.

Usage of SnmpVerify

Run the executable for the appropriate machine type. It will bind to a UDP port and begin listening for an SNMP message. By default, the program will use port 1113 but you may specify a different port on the commandline if you prefer. It is especially useful on Unix when the default port is used. Usage:
```
	SnmpVerify [port]
```
Run your SNMP program, pointing it at the SnmpVerify program. Specifically, make sure your program is sending to the IP address of the machine you are using for SnmpVerify (or 127.0.0.1 if running on the same machine) and that it is binding to the port used by SnmpVerify.
When SnmpVerify receives a message, it will begin parsing the message, reporting its progress at each step. The program is expecting a 'get' request for the system description variable. This feedback should help you diagnose errors in the construction of your SNMP requests.
Once SnmpVerify reports that your message is formatted properly, you should modify your program to run against a real SNMP agent. This is essential as parsing the response from the agent is as central to the project as constructing the request. The completed project must run against a "real" SNMP agent and not SnmpVerify.

Expected debug information in SnmpVerify:

C:\Documents and Settings\Yu Liu\My Documents\Snmp\Debug>snmpverify
Listening on port 1113 for SNMP get-request sysDescr ...
Received message from 127.0.0.1


Checking for SNMP 'get'...
Read SNMP GET

Checking length of SNMP PDU...
Read length of 25 for SNMP PDU

Checking for request id...
Read SNMP request id 1

Checking for error statusid...
Read SNMP error status id 0

Checking for error index...
Read SNMP error index 0

Checking for sequence to wrap all varbinds...
Read length of 14 for all varbinds

Checking for sequence to wrap first varbind...
Read length of 12 for varbind

Checking for sysdescr.0 oid...
Read sysdescr.0 oid

Checking for null value to be filled in on return...
Read null value

Message formatted properly.

...

Jim's comments on the file:

From: Jim Durrell [mailto:JimD@CoManage.net]
Sent: Tuesday, November 07, 2000 3:42 PM
To: Yu Liu
Cc: John Nau
Subject: Project help

Hi Yu,

I've been receiving a number of requests from people who are having trouble
getting their SNMP projects (the first one) to work properly.  The big
obstacle is that SNMP agents (by design) do not respond to misformatted
requests and therefore students are having a difficult time getting hints as
to what is wrong with their messages.  

To address this, I've written a program that will provide some diagnostics
about the messages students are developing.  Could you please post the
attached NT executable to the web site?  ...

Thanks,
   -- jim

Yu Liu

Last modified: Mon Nov 20 13:54:50 Eastern Standard Time 2000