ICAP Setting for Maximum number Connections for Request and Response Modes

Ideally, you would have one ICAP connection available for every concurrent HTTP connection you expect to service. However, the optimal value for this setting depends on the following:  
 

• The size of the IWSVA server (CPU, memory, etc.)

• The expected amount of network traffic IWSVA will services

• Note: Some clients, such as NetCache, can multiplex ICAP connections. For example, if the client has three concurrent HTTP transactions, but only one available ICAP connection, the client will pass each item one-by-one over the single ICAP connection to the three HTTP transactions.

To manually configure the maximum number of connections for ICAP request modification and response modification:

1. Execute /usr/iwss/S99ISproxy stop

2. Open the /etc/iscan/IWSSPIProtocolIcap.pni file.

3. Modify max_tpc_proc and max_threads_per_proc in the /var/iwss/intscan.ini file. Modify respratio in the /etc/iscan/IWSSPIProtocolIcap.pni file. Note the following:

1. max respmod connection number = respratio% * max_tpc_proc * max_threads_per_proc

2. max reqmod connection number = (100 - respratio)% * max_tpc_proc * max_threads_per_proc

4. Execute /usr/iwss/S99ISproxy start

5. Note:  Trend Micro recommends that you stop the HTTP daemon using step 1 before modifying the pni file.