When you are done modifying the file, save changes then open Communicator to test your new settings. If you have multiple user profiles, changes must be made to each user profile's prefs.js in order to implement the changes for all users. The maximum number of concurrent HTTP connections to a web server. Increasing the value will only speed page loading if there is sufficient bandwidth as available bandwidth is divided among the connections, and decreasing the value may degrade performance. There is no maximum, but there is a limit of 6 open connections per browser window.
Larger values mean more data but can saturate the system on faster networks.
The time, in seconds, before a timeout error appears when attempting to contact a server or perform a DNS lookup. A value of 0 for this parameter will use the default. The time, in seconds, before a server's IP address is purged from local memory. Subsequent requests to the server will require another lookup against the DNS server. The default value is 900 seconds.