From a Linux system, using the appropriate snmp command, I can get the traffic counters on any interface, so therefore I can monitor total traffic through any interface on the ASA 5520 firewall. No problem there.
$ snmpwalk -Os -c community -v 1 firewall.address | grep Octets
ifInOctets.1 = Counter32: 2387591805
ifInOctets.2 = Counter32: 3256166813
ifInOctets.3 = Counter32: 263478072
ifInOctets.5 = Counter32: 2954139109
ifOutOctets.1 = Counter32: 3995534498
ifOutOctets.2 = Counter32: 928367724
ifOutOctets.3 = Counter32: 2103539651
ifOutOctets.5 = Counter32: 2633864984
Now, there's a couple VPN tunnels terminated on this firewall. I would like to monitor, with SNMP, the traffic through the VPN tunnels. I can't find the place in SNMP where those traffic counters are.
I did an snmpwalk on that firewall and looked at the output, but couldn't find anything that may suggest any relation to VPN.
Can somebody shed some light please?