doc.FAQ.DoUsersNeedToEmploySpecialConfigurationToOperateInAFirewalledEnvironment Single-Tier users should not need to open ports to accommodate the Single-Tier driver. However, ports may need to be opened to facilitate connections between the database native client and the database to which it connects.Multi-Tier users need to take the following action, if a firewall surrounds the machine that contains the Multi-Tier server components:Login to the machine that contains the Multi-Tier server components. Use a text editor to open the oplrqb.ini file that resides in the /bin sub-directory of the OpenLink installation. Locate the [Protocol TCP] section. For example: [Protocol TCP] PingWatchdog = No ; Send check-alive packets PingInterval = 600 ; every <PingInterval> seconds ;IPAddress = 127.0.0.1 ; Overrules found interface address PortLow = 5000 PortHigh = 5020 Make sure PortHigh is uncommented and set. PortHigh should equal PortLow + the number of concurrent connections granted by the license + a few extra ports. Record the PortLow - PortHigh range. Record the Listen port value. ( OpenLink 1.x and 3.x do not have Listen Port value.) Close oplrqb.ini. Open the Listen and PortLow - PortHigh TCP ports on the firewall. Open UDP port #60001--in addition to TCP PortLow - PortHigh --to accommodate 1.x and 3.x drivers.