[AGENT++] can get from subnet netaddress. A bug of SNMP++ or SNMP Protocol fault?

[Jochen Katz]

Hi,

> There is a subnet 192.168.0.104/255.255.255.252 where my routers
> resides. Router A has a IP address 192.168.0.105 and Router B
> 192.168.0.106
> 
> But when I provide the subnet netaddress 192.168.0.104 or subnet
> broadcast address 192.168.0.107 ,it will both get a response from
> 192.168.0.105. I use the SNMP++v3.2.16 package. Is this phenomenon
> caused by SNMP++ package or SNMP protocol?

snmp++ does not expect to receive two responses for one request, so only
the first that is received is returned. Possibly router A is faster than
router B or B just does not answer broadcast requests (you can use a
sniffer to check this).

As the SNMP standard does not define what agents should do if they
receive a request on a broadcast address, some agents answer them and
some don't.

snmp++ has a function Snmp::broadcast_discovery() that waits for
multiple answers.

Regards,
  Jochen