I am about to install an 887 for a client and he wants to know if he can get reports of all successful VPN logons, so he can see who has been on the network. What information is available from IPS logs on an 887?
Alternatively, what information could he get from IDS on an ASA?
IPS is not design to provide logs for successful VPN connections. Logs of successfully VPN connections can be gathered through syslog, and you can send the syslog messages to an external syslog server.
Here is the doc for your reference:
Similarly IPS on ASA is design for Intrusion Prevention when specific traffic matches the IPS signature. Here is more information on IPS for your reference:
Hope that helps.