The OID is not fine for a GET PDU request.
Mixing terms (GET, WALK, GETNEXT, etc.) as you like does not help you
and others.
For me it makes giving support more difficult and time consuming,
because I have to guess
and write a lot of postings to clarify stuff that is most likely not
related to the root cause.
BTW, OIDs do *not* start with a dot ("."). This leading dot is *not*
standard conform.
It is a (IMHO bad) "feature" of NET-SNMP - nothing else.
Am 12.08.2016 um 08:51 schrieb FLORENT Philippe:
I do a GET on a perfectly fine oid
- works with snmpwalk (linux cli)
- works as GET in Mib Browser (might do a walk too when I click on the GET
button)
So I managed to get the data using snmp4j tables , there it works(at least with
v 1.1)
-----Original Message-----
From: Frank Fock [mailto:f...@agentpp.com]
Sent: jeudi 11 août 2016 14:42
To: FLORENT Philippe
Cc: snmp4j@agentpp.org
Subject: Re: [SNMP4J] java.lang.NullPointerException: Context engine ID must
not be null
Hi Philippe,
It's how I wrote. You are not specifying the instance sub-identifiers. A
GETNEXT will *never* return a noSuchInstance error! (If the agent is SNMP
standard conform) Best regards Frank
Am 11.08.2016 um 11:03 schrieb FLORENT Philippe <philippe.flor...@edenred.com>:
Please help, I am really struggling with this, that OID exists, no matter I use GT or
GETNEXT, it return "no such instance"
If I look the infos on that oid : .1.3.6.1.2.1.4.20.1.2
Walk:
-------
IP-MIB::ipAdEntIfIndex.127.0.0.1 = INTEGER: 1
IP-MIB::ipAdEntIfIndex.192.168.1.128 = INTEGER: 2
snmptranslate -Td :
-------------------------
IP-MIB::ipAdEntIfIndex
ipAdEntIfIndex OBJECT-TYPE
-- FROM IP-MIB
SYNTAX INTEGER (1..2147483647)
MAX-ACCESS read-only
STATUS deprecated
DESCRIPTION "The index value which uniquely identifies the interface to
which this entry is applicable. The interface identified by
a particular value of this index is the same interface as
identified by the same value of the IF-MIB's ifIndex."
::= { iso(1) org(3) dod(6) internet(1) mgmt(2) mib-2(1) ip(4)
ipAddrTable(20) ipAddrEntry(1) 2 }
-----Original Message-----
From: Frank Fock [mailto:f...@agentpp.com]
Sent: jeudi 11 août 2016 10:26
To: FLORENT Philippe
Cc: snmp4j@agentpp.org
Subject: Re: [SNMP4J] java.lang.NullPointerException: Context engine
ID must not be null
Hi,
If walk (which is a GETNEXT in fact) and GET behave differently then most
likely you are using the wrong OID (wrong instance identifier). Sometimes the
agent is broken too.
In your case, you should put the Snmp instance in listen mode to receive
answers from the agent. See FAQ for details.
Best regards
Frank
Am 11.08.2016 um 09:29 schrieb FLORENT Philippe <philippe.flor...@edenred.com>:
Hello everyone,
- Doing a get on some OID give me "unkown instance" although they
work with snmpwalk on the command line and GET works with mib explorer
- So I try to implement an snmp walk in snmp4j but I keep getting that
error
Here is the code
I tried to use request.getContextEngineID(), but it is also null
public class SnmpProber
{
private Snmp snmp;
private UserTarget target;
private byte[] authEngineId0=null;
public SnmpProber(String ipAddress,String port,String userName,String
authPass,String privPass)
{
try
{
Address targetAddress =
GenericAddress.parse("udp:"+ipAddress+"/"+port);
TransportMapping transport = new DefaultUdpTransportMapping();
snmp = new Snmp(transport);
USM usm = new USM(SecurityProtocols.getInstance(),new
OctetString(MPv3.createLocalEngineID()), 0);
SecurityModels.getInstance().addSecurityModel(usm);
transport.listen();
target = new UserTarget();
target.setAddress(targetAddress);
target.setRetries(1);
target.setTimeout(5000);
target.setVersion(SnmpConstants.version3);
target.setSecurityLevel(SecurityLevel.AUTH_PRIV);
target.setSecurityName(new OctetString(userName));
authEngineId0 =
snmp.discoverAuthoritativeEngineID(target.getAddress(), 5000);
if(authEngineId0==null)
System.out.println("cannot connect");
else
{
// add user to the USM
UsmUser usmUser=new UsmUser(new OctetString(userName),
AuthSHA.ID,
new OctetString(authPass),
PrivAES128.ID,
new OctetString(privPass));
snmp.getUSM().addUser(new OctetString("v3DefaultUser"),
new OctetString(authEngineId0),
usmUser);
}
} catch (IOException ex) {
Logger.getLogger(SnmpProber.class.getName()).log(Level.SEVERE, null,
ex);
}
}
public boolean isOk()
{
return authEngineId0!=null;
}
class WalkCounts {
public int requests;
public int objects;
}
public List<VariableBinding> walk(String oid)
{
final List<VariableBinding> result;
result = new LinkedList<VariableBinding>();
ScopedPDU request;
request = new ScopedPDU();
request.setType(PDU.GETNEXT);
request.add(new VariableBinding(new OID(oid)));
request.setNonRepeaters(0);
OID rootOID = request.get(0).getOid();
final WalkCounts counts = new WalkCounts();
final long startTime = System.currentTimeMillis();
TreeUtils treeUtils = new TreeUtils(snmp, new
DefaultPDUFactory());
TreeListener treeListener = new TreeListener()
{
public boolean next(TreeEvent e) {
counts.requests++;
if (e.getVariableBindings() != null) {
VariableBinding[] vbs = e.getVariableBindings();
counts.objects += vbs.length;
for (int i = 0; i < vbs.length; i++) {
if (result != null) {
result.add(vbs[i]);
}
System.out.println(vbs[i].toString());
}
}
return true;
}
@Override
public void finished(TreeEvent e) {
if ((e.getVariableBindings() != null)
&& (e.getVariableBindings().length > 0)) {
next(e);
}
System.out.println("Total requests sent: "+ counts.requests);
System.out.println("Total objects received: "+ counts.objects);
System.out.println("Total walk time: "+ (System.currentTimeMillis()
- startTime)+ " milliseconds");
if (e.isError()) {
System.err.println("The following error occurred during
walk:");
System.err.println(e.getErrorMessage());
}
synchronized (this) {
this.notify();
}
}
@Override
public boolean isFinished() {
return true;
}
};
synchronized (treeListener)
{
treeUtils.getSubtree(target, rootOID, null, treeListener);
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< exception here
try
{
treeListener.wait();
}
catch (InterruptedException ex)
{
System.out.println("Tree retrieval interrupted: "+ex);
Thread.currentThread().interrupt();
}
}
return result;
}
public void Release()
{
try {
snmp.close();
} catch (IOException ex) {
Logger.getLogger(SnmpProber.class.getName()).log(Level.SEVERE, null,
ex);
}
}
}
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