Polling Multiple Devices through NAT port forwarding

madkap

Hi All

I was wondering if there is a way to poll multiple devices through port forwards on an CPE device (Cisco ADSL Router).

Example:
Remote branch office has a Cisco CPE and multiple servers behind it running NAT. The CPE has one Live IP address from the DSL provider.

Use snmp port 161 to poll CPE device for bandwidth/network usage, then on the CPE port forward port 162 to a internal windows server and port 163 to poll internal unix server.

At the moment you can define custom snmp ports however when you add the second device on the new port number it just overwrites the existing entry with the new details instead of adding a seperate node entry (tested on Orion 8.5).

Should this be possible?

Regards
Brendan

brian.austin

I've done this on firewalls using a double-NAT technique.  It doesn't always work, though.

On the NPM, define three separate private IPs (ex: 192.168.100.1, .2, .3)

On the NPM side firewall, set up outbound NAT and add definitions:
192.168.100.1 = 1.2.3.4:161
192.168.100.2 = 1.2.3.4:162
192.168.100.3 = 1.2.3.4:163

Then set up the Cisco firewall to NAT the inbound IP:port combinations to internal IP addresses.  If you swap them back to their standard ports, you don't have to adjust the host's SNMP port number, either.

The few times I've needed to do this, I haven't used SNMP Traps, so outbound from the non-NPM side wasn't necessary.  I'm not sure what you'll have to do for that direction.