The Net-SNMP's snmptrapd software now includes embedded Perl trap handling capabilities, allowing users to customize how traps are handled.
I recently had the opportunity to use NetSNMP::TrapReceiver, a Perl module that allows you to register Perl subroutines into the Net-SNMP snmptrapd process. However, it is worth noting that for this module to work, Net-SNMP has to be configured using --enable-embedded-perl. The registration of functions can then be done through the snmptrapd.conf configuration file.
It’s important to note that this module cannot be used in a regular Perl script to receive traps. It is intended solely for embedded use within the snmptrapd daemon.
Within the snmptrapd.conf file, you can use the keyword "perl" to call any Perl expression, and with this ability, you can use NetSNMP::TrapReceiver to register functions. These functions are called every time a given notification (a trap or an inform) is received. Registered functions are called with two arguments.
The first argument is a reference to a hash containing information about how the trap was received (what version of the SNMP protocol was used, where it came from, what SNMP user name or community name it was sent under, etc.). The second argument is a reference to an array containing the variable bindings (OID and value information) that define the notification itself. Each variable is itself a reference to an array containing three values: a NetSNMP::OID object, the value that came associated with it, and the value's numeric type (see NetSNMP::ASN for details on SNMP typing information).
Subroutines are registered using the NetSNMP::TrapReceiver::register function, which takes two arguments. The first is a string that describes the notification you want to register for (e.g., "linkUp" or "MyMIB::MyTrap" or ".1.3.6.1.4.1.2021...."). Two special keywords can be used in place of an OID: "default" and "all." The "default" keyword indicates that you want your handler to be called in the case where no other handlers are called. The "all" keyword indicates that the handler should ALWAYS be called for every notification.
Overall, I found NetSNMP::TrapReceiver to be extremely useful for registering Perl subroutines within the Net-SNMP snmptrapd process. While it has some limitations, it’s easy to use and very efficient once you have it set up. I’d highly recommend it to anyone who needs this kind of functionality.
It’s important to note that this module cannot be used in a regular Perl script to receive traps. It is intended solely for embedded use within the snmptrapd daemon.
Within the snmptrapd.conf file, you can use the keyword "perl" to call any Perl expression, and with this ability, you can use NetSNMP::TrapReceiver to register functions. These functions are called every time a given notification (a trap or an inform) is received. Registered functions are called with two arguments.
The first argument is a reference to a hash containing information about how the trap was received (what version of the SNMP protocol was used, where it came from, what SNMP user name or community name it was sent under, etc.). The second argument is a reference to an array containing the variable bindings (OID and value information) that define the notification itself. Each variable is itself a reference to an array containing three values: a NetSNMP::OID object, the value that came associated with it, and the value's numeric type (see NetSNMP::ASN for details on SNMP typing information).
Subroutines are registered using the NetSNMP::TrapReceiver::register function, which takes two arguments. The first is a string that describes the notification you want to register for (e.g., "linkUp" or "MyMIB::MyTrap" or ".1.3.6.1.4.1.2021...."). Two special keywords can be used in place of an OID: "default" and "all." The "default" keyword indicates that you want your handler to be called in the case where no other handlers are called. The "all" keyword indicates that the handler should ALWAYS be called for every notification.
Overall, I found NetSNMP::TrapReceiver to be extremely useful for registering Perl subroutines within the Net-SNMP snmptrapd process. While it has some limitations, it’s easy to use and very efficient once you have it set up. I’d highly recommend it to anyone who needs this kind of functionality.
What's New
Version 5.0401: N/A