Glossary of Technical Terms A B C D E F G H I J K L M N O P Q R S T U V W X Y Z #Firewall Firewalls are comprised of hardware and/or software components. These components protect private networks from unsolicited, public network traffic. OpenLink's Multi-Tier drivers can operate through a firewall. However, TCP Ports High through Low. You may find the values--which are passed by PortHigh and PortLow--in the [Protocol TCP] section of the OpenLink Session Rules Book.Note: OpenLink's 1.x and 3.x users must also open UDP port #60001 on their firewalls. Use of UDP port #60001 has been deprecated in more recent builds.