SNMPAgent Class

Properties   Methods   Events   Config Settings   Errors  

The SNMPAgent class is used to implement UDP-based SNMP Agent Applications.

Syntax

ipworkssnmp.Snmpagent

Remarks

The SNMPAgent class implements a UDP-based standard SNMP Agent as specified in the SNMP RFCs. The class supports SNMP v1, v2c, and v3.

The class provides both encoding/decoding and transport capabilities, making the task of developing a custom SNMP agent as simple as setting a few key properties and handling a few events. SNMP data such as SNMP object id-s (OID-s) are exchanged as text strings, thus further simplifying the task of handling them.

The class is activated/deactivated by calling the Activate or Deactivate method. These methods enable or disable sending and receiving. The activation status can be found in the Active property.

The class operates asynchronously. Requests are received through events such as GetRequest, GetBulkRequest, GetNextRequest, etc. and the corresponding responses are automatically sent when the events return. Traps are sent through the SendTrap method.

SNMPv3 USM security passwords are requested through the GetUserPassword event, and event parameters such as User and SecurityLevel provide information about the security attributes of received requests, and enable granular decision capability about what to provide and what not to provide. The SendSecureTrap method is used to send authenticated (secure) SNMPv3 traps.

The AddUser, RemoveUser, ShowCache, and ClearCache methods are used to manage an internal authentication cache. This internal cache can be used as an alternative to the GetUserPassword event, automatically checking the cache against the security parameters provided in the request signature.

SNMP OIDs, types, and values are provided in the Objects collection of SNMP objects for both sent and received packets.

Other packet information is provided through corresponding event parameters, such as Community, or RequestId.

Property List

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The following is the full list of the properties of the class with short descriptions. Click on the links for further details.

Method List

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The following is the full list of the methods of the class with short descriptions. Click on the links for further details.

Event List

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The following is the full list of the events fired by the class with short descriptions. Click on the links for further details.

Config Settings

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The following is a list of config settings for the class with short descriptions. Click on the links for further details.

AcceptData Property (SNMPAgent Class)

Enables or disables data reception.

Syntax

public boolean isAcceptData();


public void setAcceptData(boolean acceptData);

Default Value

True

Remarks

Setting the property to False temporarily disables data reception. Setting the property to True re-enables data reception.

This property is not available at design time.

Active Property (SNMPAgent Class)

Indicates whether the class is active.

Syntax

public boolean isActive();


public void setActive(boolean active);

Default Value

False

Remarks

This property indicates whether the class is currently active and can send or receive data.

The class will be automatically activated if it is not already and you attempt to perform an operation which requires the class to be active.

Note: Use the Activate or Deactivate method to control whether the class is active.

This property is not available at design time.

LocalEngineId Property (SNMPAgent Class)

The Engine Id of the SNMP Agent.

Syntax

public byte[] getLocalEngineId();


public void setLocalEngineId(byte[] localEngineId);

Default Value

""

Remarks

This property is only used for SNMPv3 packets (when SNMPVersion is 3).

LocalHost Property (SNMPAgent Class)

The name of the local host or user-assigned IP interface through which connections are initiated or accepted.

Syntax

public String getLocalHost();


public void setLocalHost(String localHost);

Default Value

""

Remarks

The LocalHost property contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

In multi-homed hosts (machines with more than one IP interface) setting LocalHost to the value of an interface will make the class initiate connections (or accept in the case of server classs) only through that interface.

If the class is connected, the LocalHost property shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multi-homed hosts (machines with more than one IP interface).

NOTE: LocalHost is not persistent. You must always set it in code, and never in the property window.

LocalPort Property (SNMPAgent Class)

The port in the local host where the class listens.

Syntax

public int getLocalPort();


public void setLocalPort(int localPort);

Default Value

161

Remarks

The LocalPort property must be set before the class is activated (Active is set to True). It instructs the class to bind to a specific port (or communication endpoint) in the local machine (default 161).

You may also set LocalPort to 0. This allows the TCP/IP stack to choose a port at random. The value chosen is provided via the LocalPort property after the class is activated through the Active property.

LocalPort cannot be changed once the class is Active. Any attempt to set the LocalPort property when the class is Active will generate an error.

Note: on macOS and iOS, root permissions are required to set LocalPort to any value below 1024.

Objects Property (SNMPAgent Class)

The objects in the current request.

Syntax

public SNMPObjectList getObjects();


public void setObjects(SNMPObjectList objects);

Remarks

The SNMP objects being sent or received in the current request. The collection is first cleared, then populated every time an SNMP packet is received. It is also used to create outgoing SNMP packets.

This collection is indexed from 0 to size -1.

Please refer to the SNMPObject type for a complete list of fields.

RequestId Property (SNMPAgent Class)

The request-id to mark outgoing packets with.

Syntax

public int getRequestId();


public void setRequestId(int requestId);

Default Value

1

Remarks

If a custom value is needed for RequestId, the property must be set before sending the request. The class increments RequestId automatically after sending each packet.

This property is not available at design time.

SNMPVersion Property (SNMPAgent Class)

Version of SNMP used for outgoing requests (traps).

Syntax

public int getSNMPVersion();


public void setSNMPVersion(int SNMPVersion);


Enumerated values:
  public final static int snmpverV1 = 1;
  public final static int snmpverV2c = 2;
  public final static int snmpverV3 = 3;

Default Value

2

Remarks

This property takes one of the following values:

SysUpTime Property (SNMPAgent Class)

Time passed since the agent was initialized (in hundredths of a second).

Syntax

public long getSysUpTime();


public void setSysUpTime(long sysUpTime);

Default Value

0

Remarks

This property is used when sending SNMP traps, and it normally provides the time since the system was restarted in 1/100s of a second.

If another value is desired, you may set this property to a custom value. From that point on, SysUpTime will return the value set plus time elapsed.

This property is not available at design time.

Activate Method (Snmpagent Class)

Activates the class.

Syntax

public void activate();

Remarks

This method activates the component and will allow it to send or receive data.

The class will be automatically activated if it is not already and you attempt to perform an operation which requires the class to be active.

Note: Use the Active property to check whether the component is active.

AddUser Method (Snmpagent Class)

Adds a user to the internal authentication cache.

Syntax

public void addUser(String user, int authenticationProtocol, String authenticationPassword, int encryptionAlgorithm, String encryptionPassword);

Remarks

The internal authentication cache can be used as an alternative to the GetUserPassword event, automatically checking the cache against the security parameters provided in the request signature.

The ShowCache method is used to show the contents of the internal authentication cache.

The ClearCache method can be used to completely clear the cache.

Valid Authentication Protocols are:

Valid Encryption Algorithms are:

NOTE: Specifying an authentication protocol of 0 is a special case where the class will attempt to verify users with all valid authentication protocols.

ClearCache Method (Snmpagent Class)

Clears the internal authentication database.

Syntax

public void clearCache();

Remarks

All user records are removed from the internal authentication cache as a result of this call.

Config Method (Snmpagent Class)

Sets or retrieves a configuration setting.

Syntax

public String config(String configurationString);

Remarks

Config is a generic method available in every class. It is used to set and retrieve configuration settings for the class.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

Deactivate Method (Snmpagent Class)

Deactivates the class.

Syntax

public void deactivate();

Remarks

This method deactivates the component and will prohibit it from sending and receiving data.

Note: Use the Active property to check whether the component is active.

DoEvents Method (Snmpagent Class)

Processes events from the internal message queue.

Syntax

public void doEvents();

Remarks

When DoEvents is called, the class processes any available events. If no events are available, it waits for a preset period of time, and then returns.

HashPasswords Method (Snmpagent Class)

Hashes all passwords in the cache.

Syntax

public void hashPasswords();

Remarks

Forces computation of all passwords hashes in the cache. Used together with the HashPassword event to enable implementations of external password hash storage.

RemoveUser Method (Snmpagent Class)

Removes the user specified by User from the internal authentication cache.

Syntax

public void removeUser(String user);

Remarks

The internal authentication cache can be used as an alternative to the GetUserPassword event, automatically checking the cache against the security parameters provided in the request signature.

The ShowCache method is used to show the contents of the internal authentication cache.

The ClearCache method can be used to completely clear the cache.

Reset Method (Snmpagent Class)

Clears the object arrays.

Syntax

public void reset();

Remarks

Clears the object arrays, and sets the trap and error properties to their default values. This is useful for reinitializing all the properties that are used to create outgoing packets before building a new packet.

Note: SNMPVersion will be reset to snmpverV2c (2).

SendResponse Method (Snmpagent Class)

Sends a response packet to a Get, Get-Next, Get-Bulk, or Set request.

Syntax

public void sendResponse(String remoteHost, int remotePort, int requestId, String community, int errorStatus, int errorIndex);

Remarks

Use this method to send asynchronous response packets. A valid RequestId must be specified. SendResponse sends an unauthenticated response packet. Depending upon the value of the SNMPVersion property, the packet is constructed as an SNMPv1, SNMPv2c, or SNMPv3 (unauthenticated) response PDU. To send authenticated or encrypted SNMPv3 responses, use SendSecureResponse

The RemoteHost and RemotePort parameters are used to determine where the response is to be sent. The object identifiers, types, and values for the request are taken from the Objects collection. The RequestId, Community, ErrorStatus, and ErrorIndex parameters are used to specify other properties of the response.

SendSecureResponse Method (Snmpagent Class)

Sends an authenticated and/or encrypted SNMPv3 response.

Syntax

public void sendSecureResponse(String remoteHost, int remotePort, int requestId, int messageId, int errorStatus, int errorIndex, String user, int authenticationProtocol, String authenticationPassword, int encryptionAlgorithm, String encryptionPassword);

Remarks

Similar to the SendResponse method except that User, Authentication Protocol, and AuthenticationPassword are used to authenticate the response. EncryptionAlgorithm and EncryptionPassword (if not empty) are used to encrypt the response.

The MessageId argument must match the MessageId parameter obtained from the GetRequest, GetNextRequest, SetRequest, or GetBulkRequest event.

The user and password arguments used to send the response will be added to the internal user cache. If the user is already in the cache, its passwords will be updated with those supplied.

Valid Authentication Protocols are:

Valid Encryption Algorithms are:

SendSecureTrap Method (Snmpagent Class)

Sends an authenticated and/or encrypted SNMPv3 trap.

Syntax

public void sendSecureTrap(String remoteHost, String trapOID, String user, int authenticationProtocol, String authenticationPassword, int encryptionAlgorithm, String encryptionPassword);

Remarks

Similar to the SendTrap method except that User, AuthenticationPassword, and Authentication Protocol are used to authenticate the trap. EncryptionPassword (if not empty) and EncryptionAlgorithm are used to encrypt the message.

The user and password arguments used to send the trap will be added to the internal user cache. If the user is already in the cache, its passwords will be updated with those supplied.

Valid Authentication Protocols are:

Valid Encryption Algorithms are:

SendTrap Method (Snmpagent Class)

Sends an SNMP Trap.

Syntax

public void sendTrap(String remoteHost, String trapOID);

Remarks

Depending upon the value of the SNMPVersion property, the packet is constructed as an SNMPv1 or SNMPv2 Trap PDU. The following configuration settings provide more control about how traps are generated: TrapPort, TrapAgentAddress, TrapCommunity, TrapEnterprise. The SysUpTime property provides the trap timestamp.

SendTrap sends an unauthenticated trap. The SendSecureTrap method is used to send authenticated SNMPv3 traps.

If any values are provided in the Objects collection, they are sent unchanged. In the case of an SNMPv2 or SNMPv3 Trap, if Objects has a count that is equal to 0, the following values are set: sysUpTime.0 equal to SysUpTime and snmpTrapOID.0 equal to TrapOID.

For SNMPv2 and SNMPv3 Traps, TrapOID must contain the full OID of the Trap. For SNMPv1, TrapOID must be a string of the form "generic.specific" where generic and specific are numeric values providing the Trap Generic Type and Specific Type.

For SNMPv1, TrapOID must be of the form "GenericTrap.SpecificTrap". These values are sent in the PDU header. TrapAgentAddress and TrapEnterprise are taken from the corresponding configuration settings.

Additionally, the following symbolic values are recognized and translated as follows:

ShowCache Method (Snmpagent Class)

Lists all entries in the internal user authentication cache.

Syntax

public void showCache();

Remarks

A CacheEntry event is fired for every record in the internal user authentication cache.

The internal authentication cache can be used as an alternative to the GetUserPassword event, automatically checking the cache against the security parameters provided in the request signature.

The ShowCache method is used to show the contents of the internal authentication cache.

The ClearCache method can be used to completely clear the cache.

Value Method (Snmpagent Class)

Returns the value corresponding to an OID.

Syntax

public String value(String OID);

Remarks

If the OID does not exist in the Objects collection, a trappable error is generated.

Please refer to the SNMPObject type for more information.

BadPacket Event (Snmpagent Class)

Fired for erroneous and/or malformed messages.

Syntax

public class DefaultSnmpagentEventListener implements SnmpagentEventListener {
  ...
  public void badPacket(SnmpagentBadPacketEvent e) {}
  ...
}

public class SnmpagentBadPacketEvent {
  public byte[] packet;
  public String sourceAddress;
  public int sourcePort;
  public int errorCode;
  public String errorDescription;
  public boolean report;
}

Remarks

The full message is provided in the Packet parameter.

The BadPacket event is also fired when authentication fails for received packets due to a bad password or other reasons.

If the Report parameter is set to True, an unauthenticated error report will be sent to the client, otherwise the packet will be silently ignored.

Please refer to the GetUserPassword event for more information concerning SNMPv3 authentication.

CacheEntry Event (Snmpagent Class)

Shows in the internal cache.

Syntax

public class DefaultSnmpagentEventListener implements SnmpagentEventListener {
  ...
  public void cacheEntry(SnmpagentCacheEntryEvent e) {}
  ...
}

public class SnmpagentCacheEntryEvent {
  public String user;
  public String authenticationProtocol;
  public String authenticationPassword;
  public String encryptionAlgorithm;
  public String encryptionPassword;
}

Remarks

CacheEntry events are triggered by a call to ShowCache. One event is fired for each user.

DiscoveryRequest Event (Snmpagent Class)

Fired when an SNMPv3 discovery packet is received.

Syntax

public class DefaultSnmpagentEventListener implements SnmpagentEventListener {
  ...
  public void discoveryRequest(SnmpagentDiscoveryRequestEvent e) {}
  ...
}

public class SnmpagentDiscoveryRequestEvent {
  public byte[] engineId;
  public int engineBoots;
  public int engineTime;
  public String user;
  public int securityLevel;
  public String sourceAddress;
  public int sourcePort;
  public boolean respond;
}

Remarks

EngineId, EngineBoots, EngineTime, and User are the values received from SourceAddress.

For SNMPv3, the User parameter shows the user that was supplied with the packet. This parameter MUST be used together with the SecurityLevel parameter which shows the level of security in the message.

The SecurityLevel parameter shows whether the request has been authenticated. If SecurityLevel is 0, the request has NOT been authenticated (i.e. the packet signature has not been verified). For an authenticated, non encrypted request, SecurityLevel is 1. For an authenticated and encrypted request, SecurityLevel is 2.

Respond is True by default, and will automatically send a response using the value in LocalEngineId. To suppress the response, set Respond to False.

The value returned to SourceAddress for EngineBoots is always 0, and EngineTime is the number of seconds since January 1st, 1970 (GMT).

Error Event (Snmpagent Class)

Information about errors during data delivery.

Syntax

public class DefaultSnmpagentEventListener implements SnmpagentEventListener {
  ...
  public void error(SnmpagentErrorEvent e) {}
  ...
}

public class SnmpagentErrorEvent {
  public int errorCode;
  public String description;
}

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the class throws an exception.

ErrorCode contains an error code and Description contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

GetBulkRequest Event (Snmpagent Class)

Fired when a GetBulkRequest packet is received.

Syntax

public class DefaultSnmpagentEventListener implements SnmpagentEventListener {
  ...
  public void getBulkRequest(SnmpagentGetBulkRequestEvent e) {}
  ...
}

public class SnmpagentGetBulkRequestEvent {
  public int requestId;
  public int messageId;
  public int SNMPVersion;
  public String community;
  public String user;
  public int securityLevel;
  public String sourceAddress;
  public int sourcePort;
  public int nonRepeaters;
  public int maxRepetitions;
  public int errorIndex;
  public int errorStatus;
  public String errorDescription;
  public boolean respond;
}

Remarks

This is only available for SNMP versions 2 and 3.

The list of variables in the SNMP packet, including optional values and types, is provided through the Objects collection. Each object is of type SNMPObject. This type describes the Oid, ObjectType, and Value of each SNMP object. These variables must be copied to another location before the event has completed executing, or they may be overridden by other events.

The SourceAddress and SourcePort parameters show the address and port of the sender as reported by the TCP/IP stack.

The MessageId parameter identifies the received request.

For SNMPv3, the User parameter shows the user that was supplied with the packet. This parameter MUST be used together with the SecurityLevel parameter which shows the level of security in the message.

The SecurityLevel parameter shows whether the request has been authenticated. If SecurityLevel is 0, the request has NOT been authenticated (i.e. the packet signature has not been verified). For an authenticated, non encrypted request, SecurityLevel is 1. For an authenticated and encrypted request, SecurityLevel is 2.

To send a response, the Respond parameter must be set to true. By default, this value is false, which means no response will be sent. The ErrorStatus parameter may also be set to a valid SNMP status code (the default value is 0, which represents no error).

The following is a list of valid SNMP status code values:

The ErrorIndex parameter indicates the index of the first variable (object) that caused an error. The default value is 0.

Variable indexes start with 0. ErrorIndex has no meaning when ErrorStatus is 0 (no error).

A GetBulkRequest is very similar to a GetNextRequest, the difference is that Getbulk performs a continuous GetNext operation based on the MaxRepitions value. The NonRepeaters value will determine the number of Objects for which a simple GetNext operation should be performed. For the remaining variables, a continuous GetNext operation is performed based on the MaxRepitions value.

So if you send a request containing X objects, the agent will perform N simple GetNext operations and M continuous GetNext operations X - N times. With X being the number of objects received, N being the number of NonRepeaters, and M being the number of MaxRepitions. Thus the SNMPMgr is expecting to receive N + M x (X - N) objects, assuming that each object has M successors.

GetNextRequest Event (Snmpagent Class)

Fired when a GetNextRequest packet is received.

Syntax

public class DefaultSnmpagentEventListener implements SnmpagentEventListener {
  ...
  public void getNextRequest(SnmpagentGetNextRequestEvent e) {}
  ...
}

public class SnmpagentGetNextRequestEvent {
  public int requestId;
  public int messageId;
  public int SNMPVersion;
  public String community;
  public String user;
  public int securityLevel;
  public String sourceAddress;
  public int sourcePort;
  public int errorIndex;
  public int errorStatus;
  public String errorDescription;
  public boolean respond;
}

Remarks

The list of variables in the SNMP packet, including optional values and types, is provided through the Objects collection. Each object is of type SNMPObject. This type describes the Oid, ObjectType, and Value of each SNMP object. These variables must be copied to another location before the event has completed executing, or they may be overridden by other events.

The SourceAddress and SourcePort parameters show the address and port of the sender as reported by the TCP/IP stack.

The MessageId parameter identifies the received request.

For SNMPv3, the User parameter shows the user that was supplied with the packet. This parameter MUST be used together with the SecurityLevel parameter which shows the level of security in the message.

The SecurityLevel parameter shows whether the request has been authenticated. If SecurityLevel is 0, the request has NOT been authenticated (i.e. the packet signature has not been verified). For an authenticated, non encrypted request, SecurityLevel is 1. For an authenticated and encrypted request, SecurityLevel is 2.

To send a response, the Respond parameter must be set to true. By default, this value is false, which means no response will be sent. The ErrorStatus parameter may also be set to a valid SNMP status code (the default value is 0, which represents no error).

The following is a list of valid SNMP status code values:

The ErrorIndex parameter indicates the index of the first variable (object) that caused an error. The default value is 0.

Variable indexes start with 0. ErrorIndex has no meaning when ErrorStatus is 0 (no error).

GetRequest Event (Snmpagent Class)

Fired when a GetRequest packet is received.

Syntax

public class DefaultSnmpagentEventListener implements SnmpagentEventListener {
  ...
  public void getRequest(SnmpagentGetRequestEvent e) {}
  ...
}

public class SnmpagentGetRequestEvent {
  public int requestId;
  public int messageId;
  public int SNMPVersion;
  public String community;
  public String user;
  public int securityLevel;
  public String sourceAddress;
  public int sourcePort;
  public int errorIndex;
  public int errorStatus;
  public String errorDescription;
  public boolean respond;
}

Remarks

The list of variables in the SNMP packet, including optional values and types, is provided through the Objects collection. Each object is of type SNMPObject. This type describes the Oid, ObjectType, and Value of each SNMP object. These variables must be copied to another location before the event has completed executing, or they may be overridden by other events.

The SourceAddress and SourcePort parameters show the address and port of the sender as reported by the TCP/IP stack.

The MessageId parameter identifies the received request.

For SNMPv3, the User parameter shows the user that was supplied with the packet. This parameter MUST be used together with the SecurityLevel parameter which shows the level of security in the message.

The SecurityLevel parameter shows whether the request has been authenticated. If SecurityLevel is 0, the request has NOT been authenticated (i.e. the packet signature has not been verified). For an authenticated, non encrypted request, SecurityLevel is 1. For an authenticated and encrypted request, SecurityLevel is 2.

To send a response, the Respond parameter must be set to true. By default, this value is false, which means no response will be sent. The ErrorStatus parameter may also be set to a valid SNMP status code (the default value is 0, which represents no error).

The following is a list of valid SNMP status code values:

The ErrorIndex parameter indicates the index of the first variable (object) that caused an error. The default value is 0.

Variable indexes start with 0. ErrorIndex has no meaning when ErrorStatus is 0 (no error).

GetUserPassword Event (Snmpagent Class)

Retrieves a password associated with a user.

Syntax

public class DefaultSnmpagentEventListener implements SnmpagentEventListener {
  ...
  public void getUserPassword(SnmpagentGetUserPasswordEvent e) {}
  ...
}

public class SnmpagentGetUserPasswordEvent {
  public int passwordType;
  public String user;
  public String password;
  public int algorithm;
}

Remarks

The GetUserPassword event is fired after initial inspection of SNMPv3 requests.

The type of password required is provided in the PasswordType parameter: 1 for authentication, and 2 for encryption (privacy).

The password corresponding to User (if any) must be provided in the Password parameter. If the password is valid, processing will continue to other events such as GetRequest, SetRequest, etc.

If the PasswordType parameter is 1 (authentication is used), the Algorithm parameter can be set. Possible values are:

If the PasswordType parameter is 2 (encryption is used), the Algorithm parameter must also be set. Possible values are:

If the password does not match the signature in the request, a BadPacket event will be fired, at which point you can decide whether to report the error to the client (see the description of the BadPacket event for more information).

If the User is invalid or unknown, set the password to empty string (default) to ignore the request. This will result in a BadPacket event being fired, at which point you can decide whether to report the error to the client or not.

GetUserSecurityLevel Event (Snmpagent Class)

Sets the security level for an incoming packet.

Syntax

public class DefaultSnmpagentEventListener implements SnmpagentEventListener {
  ...
  public void getUserSecurityLevel(SnmpagentGetUserSecurityLevelEvent e) {}
  ...
}

public class SnmpagentGetUserSecurityLevelEvent {
  public String user;
  public byte[] engineId;
  public int securityLevel;
}

Remarks

The GetUserSecurityLevel event is fired after the first inspection of each SNMPv3 request. The SecurityLevel parameter determines the level of security for the message.

On entry, the SecurityLevel parameter contains the default security level for User if the user is located in the internal cache, or if the User is not found in the cache, the SecurityLevel will be -1.

The value of SecurityLevel upon exiting the event, determines how the message will be processed:

HashPassword Event (Snmpagent Class)

Fired before and after a password is hashed.

Syntax

public class DefaultSnmpagentEventListener implements SnmpagentEventListener {
  ...
  public void hashPassword(SnmpagentHashPasswordEvent e) {}
  ...
}

public class SnmpagentHashPasswordEvent {
  public String password;
  public int authAlgorithm;
  public String hash;
}

Remarks

SNMPv3 passwords are hashed in order to obtain authentication and encryption keys. This is an expensive operation, and in certain situations it may be preferable to store the hashed passwords externally and supply them on demand.

If a hash is required, the event fires with an empty string in the Hash parameter. In this case, you can choose to supply a value for the hash and stop the class from computing the hash.

The event also fires every time a hash is computed. In this case, the Hash parameter contains the value of the computed hash.

AuthAlgorithm contains either 1 for HMAC-MD5-96, 2 for HMAC-SHA-96 or 3 for HMAC-192-SHA-256

PacketTrace Event (Snmpagent Class)

Fired for every packet sent or received.

Syntax

public class DefaultSnmpagentEventListener implements SnmpagentEventListener {
  ...
  public void packetTrace(SnmpagentPacketTraceEvent e) {}
  ...
}

public class SnmpagentPacketTraceEvent {
  public byte[] packet;
  public int direction;
  public String packetAddress;
  public int packetPort;
}

Remarks

The PacketTrace event shows all the packets sent or received by the class.

Packet contains the full contents of the datagram.

Direction shows the direction of the packet: 1 for incoming packets, and 2 for outgoing packets.

In the case of an incoming packet, PacketAddress and PacketPort identify the source of the packet.

In the case of an outgoing packet, PacketAddress and PacketPort identify the destination of the packet.

ReadyToSend Event (Snmpagent Class)

Fired when the class is ready to send data.

Syntax

public class DefaultSnmpagentEventListener implements SnmpagentEventListener {
  ...
  public void readyToSend(SnmpagentReadyToSendEvent e) {}
  ...
}

public class SnmpagentReadyToSendEvent {
}

Remarks

The ReadyToSend event indicates that the underlying TCP/IP subsystem is ready to accept data after a failed DataToSend.

Report Event (Snmpagent Class)

Fired when a Report packet is received.

Syntax

public class DefaultSnmpagentEventListener implements SnmpagentEventListener {
  ...
  public void report(SnmpagentReportEvent e) {}
  ...
}

public class SnmpagentReportEvent {
  public int requestId;
  public int SNMPVersion;
  public String community;
  public String user;
  public int securityLevel;
  public String sourceAddress;
  public int sourcePort;
  public int errorIndex;
  public int errorStatus;
  public String errorDescription;
}

Remarks

For SNMPv3, the User parameter shows the user that was supplied with the packet. This parameter MUST be used together with the SecurityLevel parameter which shows the level of security in the message.

The SecurityLevel parameter shows whether the request has been authenticated. If SecurityLevel is 0, the request has NOT been authenticated (i.e. the packet signature has not been verified). For an authenticated, non encrypted request, SecurityLevel is 1. For an authenticated and encrypted request, SecurityLevel is 2.

The list of variables in the SNMP packet, including optional values and types, is provided through the Objects collection. Each object is of type SNMPObject. This type describes the Oid, ObjectType, and Value of each SNMP object. These variables must be copied to another location before the event has completed executing, or they may be overridden by other events.

The SourceAddress and SourcePort parameters show the address and port of the sender as reported by the TCP/IP stack.

SetRequest Event (Snmpagent Class)

Fired when a SetRequest packet is received.

Syntax

public class DefaultSnmpagentEventListener implements SnmpagentEventListener {
  ...
  public void setRequest(SnmpagentSetRequestEvent e) {}
  ...
}

public class SnmpagentSetRequestEvent {
  public int requestId;
  public int messageId;
  public int SNMPVersion;
  public String community;
  public String user;
  public int securityLevel;
  public String sourceAddress;
  public int sourcePort;
  public int errorIndex;
  public int errorStatus;
  public String errorDescription;
  public boolean respond;
}

Remarks

The list of variables in the SNMP packet, including optional values and types, is provided through the Objects collection. Each object is of type SNMPObject. This type describes the Oid, ObjectType, and Value of each SNMP object. These variables must be copied to another location before the event has completed executing, or they may be overridden by other events.

The SourceAddress and SourcePort parameters show the address and port of the sender as reported by the TCP/IP stack.

The MessageId parameter identifies the received request.

For SNMPv3, the User parameter shows the user that was supplied with the packet. This parameter MUST be used together with the SecurityLevel parameter which shows the level of security in the message.

The SecurityLevel parameter shows whether the request has been authenticated. If SecurityLevel is 0, the request has NOT been authenticated (i.e. the packet signature has not been verified). For an authenticated, non encrypted request, SecurityLevel is 1. For an authenticated and encrypted request, SecurityLevel is 2.

To send a response, the Respond parameter must be set to true. By default, this value is false, which means no response will be sent. The ErrorStatus parameter may also be set to a valid SNMP status code (the default value is 0, which represents no error).

The following is a list of valid SNMP status code values:

The ErrorIndex parameter indicates the index of the first variable (object) that caused an error. The default value is 0.

Variable indexes start with 0. ErrorIndex has no meaning when ErrorStatus is 0 (no error).

SNMPObject Type

The current SNMP object.

Remarks

This type defines an SNMP object. Each object has an Oid, ObjectType, and Value. These values are populated by the class when incoming packets are received. You may use these fields to define objects to be used in outgoing packets.

Fields

Constructors

public SNMPObject();

public SNMPObject( oid);

public SNMPObject( oid,  value);

public SNMPObject( oid,  value,  SNMPObjectType);

Config Settings (Snmpagent Class)

The class accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

SNMPAgent Config Settings

UDP Config Settings

Socket Config Settings

Base Config Settings

Trappable Errors (Snmpagent Class)

SNMPAgent Errors

	201   Timeout.
	301   Bad Object Index.
	302   Value exceeds maximum number of objects allowed.
	303   The value must be an IP address in dotted format.
	305   Unsupported SNMP version.
	306   Unknown PDU type.
	307   The class is busy performing the current action.
	308   Verification failed.
	309   Missing password for Verification.
	310   Missing signature.
	311   Missing remote time.
	312   Missing timeout value.
	313   Decryption Failed.
	314   Missing password for decryption.
	315   Not encrypted.
	316   Security model not supported.
	317   Defective packet
	318   Not from bound point.
	319   Operation not permitted in current role.
	320   Bad packet.
	321   Message not authenticated.
	322   No such oid.
	323   Missing privacy parameter.
	324   Bad engine id.
	325   Bad time frame.
	326   Bad user name.
	327   Security level was not accepted.
	328   Discovery failed.
	329   Incorrect key length.
	330   No authentication password supplied.

UDP Errors

	104   UDP is already Active.
	106   You cannot change the LocalPort while the class is Active.
	107   You cannot change the LocalHost at this time. A connection is in progress.
	109   The class must be Active for this operation.
	112   Cannot change MaxPacketSize while the class is Active.
	113   Cannot change ShareLocalPort option while the class is Active.
	114   Cannot change RemoteHost when UseConnection is set and the class Active.
	115   Cannot change RemotePort when UseConnection is set and the class is Active.
	116   RemotePort can't be zero when UseConnection is set. Please specify a valid service port number.
	117   Cannot change UseConnection while the class is Active.
	118   Message can't be longer than MaxPacketSize.
	119   Message too short.
	434   Unable to convert string to selected CodePage

SSL Errors

	270   Cannot load specified security library.
	271   Cannot open certificate store.
	272   Cannot find specified certificate.
	273   Cannot acquire security credentials.
	274   Cannot find certificate chain.
	275   Cannot verify certificate chain.
	276   Error during handshake.
	280   Error verifying certificate.
	281   Could not find client certificate.
	282   Could not find server certificate.
	283   Error encrypting data.
	284   Error decrypting data.

TCP/IP Errors

	10004   [10004] Interrupted system call.
	10009   [10009] Bad file number.
	10013   [10013] Access denied.
	10014   [10014] Bad address.
	10022   [10022] Invalid argument.
	10024   [10024] Too many open files.
	10035   [10035] Operation would block.
	10036   [10036] Operation now in progress.
	10037   [10037] Operation already in progress.
	10038   [10038] Socket operation on non-socket.
	10039   [10039] Destination address required.
	10040   [10040] Message too long.
	10041   [10041] Protocol wrong type for socket.
	10042   [10042] Bad protocol option.
	10043   [10043] Protocol not supported.
	10044   [10044] Socket type not supported.
	10045   [10045] Operation not supported on socket.
	10046   [10046] Protocol family not supported.
	10047   [10047] Address family not supported by protocol family.
	10048   [10048] Address already in use.
	10049   [10049] Can't assign requested address.
	10050   [10050] Network is down.
	10051   [10051] Network is unreachable.
	10052   [10052] Net dropped connection or reset.
	10053   [10053] Software caused connection abort.
	10054   [10054] Connection reset by peer.
	10055   [10055] No buffer space available.
	10056   [10056] Socket is already connected.
	10057   [10057] Socket is not connected.
	10058   [10058] Can't send after socket shutdown.
	10059   [10059] Too many references, can't splice.
	10060   [10060] Connection timed out.
	10061   [10061] Connection refused.
	10062   [10062] Too many levels of symbolic links.
	10063   [10063] File name too long.
	10064   [10064] Host is down.
	10065   [10065] No route to host.
	10066   [10066] Directory not empty
	10067   [10067] Too many processes.
	10068   [10068] Too many users.
	10069   [10069] Disc Quota Exceeded.
	10070   [10070] Stale NFS file handle.
	10071   [10071] Too many levels of remote in path.
	10091   [10091] Network subsystem is unavailable.
	10092   [10092] WINSOCK DLL Version out of range.
	10093   [10093] Winsock not loaded yet.
	11001   [11001] Host not found.
	11002   [11002] Non-authoritative 'Host not found' (try again or check DNS setup).
	11003   [11003] Non-recoverable errors: FORMERR, REFUSED, NOTIMP.
	11004   [11004] Valid name, no data record (check DNS setup).