如何在python中将SNMP通知发送到专用子网？

Question

I'm trying to write simple python app to send SNMP traps. I've already wrote MIB table and sending traps to localhost works fine.

from pysnmp.entity.rfc3413.oneliner import ntforg

ntfOrg = ntforg.NotificationOriginator()

errorIndication = ntfOrg.sendNotification(
    ntforg.CommunityData('public'),
    ntforg.UdpTransportTarget(('localhost', 162)),
    'trap',
    ntforg.MibVariable('MY-MIB', 'my_trap'),
    ( ntforg.MibVariable('MY-MIB', 'my_trap_var'), 0xAABBCCDD )
)

if errorIndication:
    print('Notification not sent: %s' % errorIndocation)

Now I need to modify code to send traps to private subnetwork.

I have its IP address, subnet mask and gateway IP. Let assume:

IP: 20.40.34.14

Subnet Mask: 255.255.255.224

Gateway: 20.40.34.10

Is there any way to solve this through proper ntforg.UdpTransportTarget(...) arguments? I looked up source code for this class ( target.py ) and internally it uses:

socket.getaddrinfo(transportAddr[0], # localhost in example
                   transportAddr[1], # 162 in example
                   socket.AF_INET,
                   socket.SOCK_DGRAM,
                   socket.IPPROTO_UDP)[0][4][:2]

Answer 1

This is not SNMP specific. Probably more relevant to IP routing.

As you get IP connectivity between hosts, just put 20.40.34.14 into UdpTransportTarget. That should work alright for as long as UDP/162 packets could reach your Notification Receiver host.

There's also an option of sending broadcast TRAPs.