Firewall configuration

You will need to verify that the following ports are open for Double-Take Availability communications:

Product	Port
Double-Take	6320
Double-Take Availability Virtual Recovery Assistant for Hyper-V	6330
Double-Take Availability for Hyper-V	6332

Double-Take Availability uses ICMP pings to monitor the source for failover. A failover monitor will not be created if ICMP is blocked (although the data and system state will still be protected). You should configure your hardware to allow ICMP pings between the source and target. If you cannot, you will have to monitor for a failure manually and create a dummy monitor at failover time that can be manually failed over. Contact technical support for assistance with this manual process.

Double-Take Availability uses WMI (Windows Management Instrumentation) which uses RPC (Remote Procedure Call). By default, RPC will use ports at random above 1024, and these ports must be open on your firewall. RPC ports can be configured to a specific range by specific registry changes and a reboot. See the Microsoft Knowledge Base article 154596 for instructions.

Double-Take Availability also relies on other Microsoft Windows ports.

• Microsoft File Share uses ports 135 through 139 for TCP and UDP communications.
• Microsoft Directory uses port 445 for TCP and UDP communications.

These ports must be open on your firewall. Check your Microsoft documentation if you need to modify these ports.

You need to configure your hardware so that the Double-Take Availability and Microsoft Windows ports are open. Since communication occurs bidirectionally, make sure you configure both incoming and outgoing traffic.

There are many types of hardware on the market, and each can be configured differently. See your hardware reference manual for instructions on setting up your particular router.