SNAT vs DNAT

The differences between SNAT and DNAT are as follows –

PARAMETERS	SNAT	DNAT
Abbreviation for	Source NAT	Destination NAT
Terminology	SNAT changes the private IP address of the source host to public IP address. It may also change the source port in the TCP/UDP headers. SNAT is typically used by internal users to access the Internet.	Destination NAT changes the destination address in IP header of a packet. It may also change the destination port in the TCP/UDP headers. DNAT is used when we need to redirect incoming packets with a destination of a public address/port to a private IP address/port inside your network.
Use Case	A client Inside LAN and behind Firewall wanted to browse Internet	A Website Hosted inside Data Center behind the Firewall and needs to be accessible to users over Internet
Address Change	SNAT changes the source address of packets passing through NAT device	DNAT changes the destination address of packets passing through the Router
Order of Operation	SNAT is performed after the routing decision is made.	DNAT is performed before the routing decision is made.
Communication Flow	When inside secured Network initiates communicates with outside world , SNAT happens	When outside insecured Network initiates communication with inside secured Network , DNAT happens
Single/Multiple hosts	SNAT allows multiple hosts on the “inside” network to get to any host on the “outside” network	DNAT allows any host on the “outside” network to get to a single host on the “inside” network

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