This is do do with the other posting here.
Basically one parameter of the net-snmp daemon lets you set it up as a relay. According to the net-snmp documentation (I've yet to experiment in depth), you can have net-snmp either relay by specific OID, OR you can use a context name parameter within the snmp request, and match that name against another agents IP address. The netsnmp agent will then match incoming snmp queries to the other agents and forward the request (act like a relay), and also pass the messages back.
In my network, I've my "general" lab network accessable corporate-wide, but theres also a private network (10.10.10.x). For security requirements I have to keep this seperate, and of course its not routable, but I have one PC that acts as a bridge for OA&M. I was hoping to set that PC up with the relayed net-snmp daemon on a private port, and then I'd be able to access the 10.10.10.x machines.
For that to work, Cacti would have to be able to :
a) Know about the relay "context name"
b) Be able to use that in the snmp-gets.
Hope thats enough. Looking in the php SNMP website I don't see where the support for the context name is, but I don't know PHP too well so maybe I've missed it.
Of course I could achieve the same thing by putting another NIC in the cacti PC, but then I'd be increasing the security risk on the corp<>Private bridge, and if I had several private networks then I wouldn't really want to have to add a new NIC for each one, just to measure the stats.