SNMPAgent Class

Properties   Methods   Events   Configuration Settings   Errors  

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

Class Name


Procedural Interface

 ipworkssnmp_snmpagent_register_callback($res, $id, $function);
 ipworkssnmp_snmpagent_set($res, $id, $index, $value);
 ipworkssnmp_snmpagent_get($res, $id, $index);
 ipworkssnmp_snmpagent_do_adduser($res, $user, $authenticationprotocol, $authenticationpassword, $encryptionalgorithm, $encryptionpassword);
 ipworkssnmp_snmpagent_do_config($res, $configurationstring);
 ipworkssnmp_snmpagent_do_removeuser($res, $user);
 ipworkssnmp_snmpagent_do_sendresponse($res, $remotehost, $remoteport, $requestid, $community, $errorstatus, $errorindex);
 ipworkssnmp_snmpagent_do_sendsecureresponse($res, $remotehost, $remoteport, $requestid, $messageid, $errorstatus, $errorindex, $user, $authenticationprotocol, $authenticationpassword, $encryptionalgorithm, $encryptionpassword);
 ipworkssnmp_snmpagent_do_sendsecuretrap($res, $remotehost, $trapoid, $user, $authenticationprotocol, $authenticationpassword, $encryptionalgorithm, $encryptionpassword);
 ipworkssnmp_snmpagent_do_sendtrap($res, $remotehost, $trapoid);
 ipworkssnmp_snmpagent_do_value($res, $oid);


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 setting the Active property. This property enables or disables sending and receiving.

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

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

AcceptDataEnables or disables data reception.
ActiveEnables or disables sending and receiving of SNMP packets.
LocalEngineIdThe Engine Id of the SNMP Agent.
LocalHostThe name of the local host or user-assigned IP interface through which connections are initiated or accepted.
LocalPortThe port in the local host where the class listens.
ObjCountThe number of records in the Obj arrays.
ObjTypeThe current object's type.
ObjIdThe current object's id which is encoded as a string of numbers separated by periods.
ObjTypeStringA string representation of the current object's ObjectType .
ObjValueThe current object's value.
RequestIdThe request-id to mark outgoing packets with.
SNMPVersionVersion of SNMP used for outgoing requests (traps).
SysUpTimeTime passed since the agent was initialized (in hundredths of a second).

Method List

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

AddUserAdds a user to the internal authentication cache.
ClearCacheClears the internal authentication database.
ConfigSets or retrieves a configuration setting.
DoEventsProcesses events from the internal message queue.
HashPasswordsHashes all passwords in the cache.
RemoveUserRemoves the user specified by User from the internal authentication cache.
ResetClears the object arrays.
SendResponseSends a response packet to a Get, Get-Next, Get-Bulk, or Set request.
SendSecureResponseSends an authenticated and/or encrypted SNMPv3 response.
SendSecureTrapSends an authenticated and/or encrypted SNMPv3 trap.
SendTrapSends an SNMP Trap.
ShowCacheLists all entries in the internal user authentication cache.
ValueReturns the value corresponding to an OID.

Event List

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

BadPacketFired for erroneous and/or malformed messages.
CacheEntryShows in the internal cache.
DiscoveryRequestFired when an SNMPv3 discovery packet is received.
ErrorInformation about errors during data delivery.
GetBulkRequestFired when a GetBulkRequest packet is received.
GetNextRequestFired when a GetNextRequest packet is received.
GetRequestFired when a GetRequest packet is received.
GetUserPasswordRetrieves a password associated with a user.
GetUserSecurityLevelSets the security level for an incoming packet.
HashPasswordFired before and after a password is hashed.
PacketTraceFired for every packet sent or received.
ReadyToSendFired when the class is ready to send data.
ReportFired when a Report packet is received.
SetRequestFired when a SetRequest packet is received.

Configuration Settings

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

AuthenticationKeyThe key to use for authentication.
CompatibilityModeWhether to operate the class in a specific compatibility mode.
ContextEngineIdSets the context engine id of the SNMP entity.
ContextNameSets the context name of the SNMP entity.
EncryptionKeyThe key to use for encryption.
ForceLocalPortForces the class to bind to a specific port.
MsgMaxSizeThe maximum supported message size.
RespondFromDestIPWhether to respond from the IP address that the request was sent to.
SourceAddressThe source address of the received packet.
SourcePortThe source port of the received packet.
TimeWindowThe time window used for SNMPv3 timeliness checking (authentication).
TrapAgentAddressThe address of the object generating the trap.
TrapCommunityThe value of the Community parameter for SNMP traps.
TrapEnterpriseThe type of the object generating the trap.
TrapPortThe port where SNMP traps are sent.
CaptureIPPacketInfoUsed to capture the packet information.
DestinationAddressUsed to get the destination address from the packet information.
DontFragmentUsed to set the Don't Fragment flag of outgoing packets.
LocalHostThe name of the local host through which connections are initiated or accepted.
LocalPortThe port in the local host where the class binds.
MaxPacketSizeThe maximum length of the packets that can be received.
QOSDSCPValueUsed to specify an arbitrary QOS/DSCP setting (optional).
QOSTrafficTypeUsed to specify QOS/DSCP settings (optional).
ShareLocalPortIf set to True, allows more than one instance of the class to be active on the same local port.
SourceIPAddressUsed to set the source IP address used when sending a packet.
SourceMacAddressUsed to set the source MAC address used when sending a packet.
UseConnectionDetermines whether to use a connected socket.
UseIPv6Whether or not to use IPv6.
AbsoluteTimeoutDetermines whether timeouts are inactivity timeouts or absolute timeouts.
FirewallDataUsed to send extra data to the firewall.
InBufferSizeThe size in bytes of the incoming queue of the socket.
OutBufferSizeThe size in bytes of the outgoing queue of the socket.
BuildInfoInformation about the product's build.
CodePageThe system code page used for Unicode to Multibyte translations.
LicenseInfoInformation about the current license.
ProcessIdleEventsWhether the class uses its internal event loop to process events when the main thread is idle.
SelectWaitMillisThe length of time in milliseconds the class will wait when DoEvents is called if there are no events to process.
UseInternalSecurityAPITells the class whether or not to use the system security libraries or an internal implementation.

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