About source NAT and LLB Rules
You can configure how traffic is routed out of the Smoothwall, including whether it's hidden behind an IP address that the Smoothwall "owns". This is source Network Address Translation (NAT). Source NAT is needed when accessing the Internet. It can either be done by the Smoothwall Filter and Firewall, or by another device between the Smoothwall and the Internet such as the gateway, or both. Typically, source NAT is carried out by the gateway. You can also specify the gateway device to direct traffic to, or a link load balancing (LLB) pool of external connections to use, including a default LLB pool to use. For a detailed description of load balancing external connections.
You can have local traffic, that is, traffic for installed services such as the Smoothwall Filter, use a load balancing pool.
Upon installation, the Smoothwall defines a rule for each gateway configured, and a “catch-all” rule for internal networks.
Source NAT rules are applied in the top-down order they're listed in the Source NAT rules table. Once a match is found, no further searching is made.