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Does the gateway (router) change the source and destination IP addresses of the IP packets passing by?

April 26, 2017destination Gateway IP ip addresses packets passing Router source

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Does the gateway (router) change the source and destination IP addresses of the IP packets passing by?

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Explain (Note that there are two cases, one involves with network address translation, NAT). Ans: Since the destination IP address will be used by other routers to forward the IP packets to its final destionation, normally it cannot be changed. The source IP address in the IP packet is used by the receiver to identify the sender and as the destination IP address for the return IP packets. The exception case are the firewalls of the destination network (or called enhanced router) and the load balancer of server clusters. The firewall may be configured with the Destination Network Address Translation (DNAT) service where the destination IP address of a packet destined to a web server, or email server, or DNS server, will be translated into a Private LAN address such as 10.0.0.2 and then forward it to a machine within DeMilitarized Zone (DMZ). Note that for the packets for return response, the firewall will change the source IP address from private LAN address back to the corresponding ex