Because one of my customers run recently in this problem, maybe it's a good idea to mention this again.
The firewall has a limit for it's maximum concurrent connections. This is necessary to limit the amount of memory allocated.
But if you reach the limit, the firewall stops to accept new connections. You may experience this as a partial loss of connectivity.
To check the number of actual connections and the peak value, run fw tab -t connections -s on the command line
[Expert@fw1]# fw tab -t connections -s
HOST NAME ID #VALS #PEAK #SLINKS
localhost connections 8158 108437 166360 378754
The memory allocation and use of connections can also be shown withfw ctl pstat.
[Expert@fw1]# fw ctl pstat
Machine Capacity Summary:
Memory used: 12% (203MB out of 1604MB) - below low watermark
Concurrent Connections: 15% (79242 out of 499900) - below low watermark
Aggressive Aging is not active
If your concurrent connections are near the limit, you can increase the number using the SmartDashboard. Just edit the properties of the gateway object under capacity optimization and set a higher value. Please note that the memory allocation will also increase when you change something here, so make sure you've got enough free memory.