Firewall marks are an easy and efficient way to group ports used for a protocol or group of related protocols. For instance, if Load Balancer Add-On is deployed to run an e-commerce site, firewall marks can be used to bundle HTTP connections on port 80 and secure, HTTPS connections on port 443. By assigning the same firewall mark to the virtual server for each protocol, state information for the transaction can be preserved because the LVS router forwards all requests to the same real server after a connection is opened.
Because of its efficiency and ease-of-use, administrators of Load Balancer Add-On should use firewall marks instead of persistence whenever possible for grouping connections. However, administrators should still add persistence to the virtual servers in conjunction with firewall marks to ensure the clients are reconnected to the same server for an adequate period of time.