A program or set of programs designed to keep unauthorized users or messages from accessing a private network. The firewall usually has rules or protocols that authorize or prohibit outside users or messages. In email, a firewall can be designed so thast messages from domains or users listed as suspect because of spamming, hacking or forging will not be delivered.
Combining Email Marketing with Other Types of Marketing
Whether you choose to do your marketing online or offline, one thing does not change. This is the concept that no single marketing strategy will be as effective as a combination of two or more marketing strategies.