HP Switch – Activating CDP Compatibility in HP V1910 Web Interface

The "event neighbor discovery" command will generate syslog messages based on CDP events. It has to be used in conjunction with EEM, but it's pretty simple to set up.

http://www.cisco.com/en/US/docs/ios/netmgmt/command/reference/nm_06.html#wp1181238

However, I don't think that these events occur as quickly as you are hoping they will. CDP is not a protocol designed for keepalives, it's for neighbor discovery. You'd probably be better off logging against link status changes (up/down) or setting up IP SLA probes to monitor the presence of a device.

Your problem is, indeed, with routing. Things in VLAN 1 are using 5.1 as the gateway, right? 5.1 doesn't know about any other internal networks. (i.e. VLAN 10) Likewise, the hosts in VLAN 1 don't know about VLAN 10.

When clientA tries to ping serverA, the packets go to the ASA and die as it doesn't know where to send them. (it's default route would send them to the internet!) When serverA tries to ping clientA, the packets go to the switch and then to clientA, but then the replies, as before, go away.

For this reason, it's common to keep the "routing hardware" and "hosts" in different networks. VLAN 1 being just the ASA and Switch. And then VLANs 10 and 11 for the two internal networks. The switch would then be the gateway for VLAN 10&11, with it's default being the ASA. The ASA would have to have static routes added telling it about the internal networks -- routed to the switch. Without this, either the ASA has to "hairpin" traffic back to the switch to reach VLAN 10, or every host in VLAN 1 needs its own route to VLAN 10 (via the switch.)