While the terms "perimeter firewall" and "external firewall" are sometimes used interchangeably, there is a subtle difference in their connotations. A perimeter firewall specifically refers to a firewall deployed at the network perimeter, acting as the primary barrier between an internal network and external networks. On the other hand, an external firewall is a broader term encompassing any firewall positioned outside the internal network, including those deployed in cloud environments, remote offices, or other external locations. In essence, all perimeter firewalls are external firewalls, but not all external firewalls are necessarily perimeter firewalls.