With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
alL2tpStatsTunnelRemoteVendorName
ALTIGA L2tp Statistics Tunnel Remote Vendor Name
1.3.6.1.4.1.3076.2.1.2.16.2.1.8
This object identifies the vendor name of the peer's L2TP implementation. If the tunnel is idle this object should maintain its value from the last time it was connected.
Back to ALTIGA-L2TP-STATS-MIB MIB page.
IPHost Network monitor allows you to monitor alL2tpStatsTunnelRemoteVendorName on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco firewalls right now.