In Cisco ASA by running ‘sh connection count’ we can check the number of open connections. By default value for half open connection is 100000 .
ciscoasa# show conn count
1931 in use, 3139 most used
We can configure the ASA to lower that value by creating class map to select the traffic
then call that class-map in the global policy .For allowing the maximum half open connection set the values for the ’embryonic-conn-max’ parameter and for the setting half open connection limit for per host set the ‘per-client-embryonic-max’ parameter.
set connection embryonic-conn-max 1100 per-client-embryonic-max 40