[AGENT++] IP addresses on informs from a logically multi-homed proxy server

[Buchan, Mike]

I am working on a Linux based system which serves as an SNMP proxy server
for several devices.  Each device is assigned an IP address so it appears to
a command generator application is not aware of the proxy server.  The Linux
system has one NIC which has a primary IP address for the systems basic
network and SNMP interface.  For each device the system is serving proxy to,
an extra IP address is assigned to the same network interface (thus
logically multi-homed).  I actually run a separate process to handle the
SNMP proxy for each device.  Each of these processes is assigned a UDP/IP
address to monitor for commands.  This is accomplished by creating an snmpx
object for in each process using the following constructor:

snmp = snmpx(status, IPaddress);

This works just fine for a command responder application.  However, I run
into a problem when I issue inform.  All informs are tagged with the base IP
address for the network interface.  This makes it impossible to tell which
device initiated the inform and thus makes it impossible to respond
appropriately.  I could fix this by including the device's IP address as a
part of the inform text but that seems like a kluge.  Is there a way to have
the logical IP address tagged to the inform instead of the base IP address
for the interface?  The next question is of course how?


Another point on informs.

We are supposed to be sending SNMPv3 informs.  However we were never
successful in attempts to generate them according to the testing software we
were using (SilverCreek).  My diagnostics at the time (almost a year ago
now) indicated an error was caught by the snmp++ software during discovery.
Has anyone successfully passed the informs tests for an SNMP notification
originator in SilverCreek?  If so, how?  What am I missing?  (I may be able
to provide more information on what we were doing at the time)

P.S.  We are currently using agent++ version 3.5.13a and snmp++ version
3.2.9a.

Thank you for any help you can provide,

Mike Buchan