Many a times while planning for a new site or upgradation of site by installing new network and security devices, question may arise that why can’t we install either of Router or Firewall instead of both to meet the requirement. Though prima facie it may look quite similar however both differ quite significantly. Router and Firewall may overlap sometimes in some features /functionalities however both are developed to meet different objective.
While Router is a layer 3 and Layer 4 device responsible for routing packets across different networks. Router supports reachability between source and destination in LAN and WAN environment. Routers utilize IGP protocols (like static, RIP, EIGRP, OSPF) and BGP for reachability to remote networks
Firewall on the other hand is responsible for controlling and screening traffic flow across different networks or zones. Firewall keeps a Flow table (State table) unlike Router and is responsible for keeping information regarding state of communication between endpoints.
Related- Zone Based Firewall Configuration Examples
Below table will provide comparison between Router and Firewall –