Building Microservices with Go

Layer 2 or 3 firewalls

Layer 2 is more commonly used for routing, as it deals purely with MAC addresses and not IP addresses, whereas layer 3 is IP-address aware. Traditionally, layer 2 was the only real way to go without adding latency, because it would perform at roughly the same speed as the wire. With increases in processing power and memory, layer 3 now performs at wire speeds. Generally, when we are looking at edge firewalls (which are generally the first entry point into your system), they will be layer 3 these days. So what does this give us? Firstly, it stops unwanted traffic at the edge: we limit the ports that are accessible to the outside world, and traffic with malicious intent is stopped at the firewall and does not get the ...