The Reply

Reply Hits Public Port

The inbound reply is addressed to the NAT public endpoint.

highlighted = computed this step

The reply arrives at the public endpoint

The inbound destination is public address 203.0.113.5 port 62000.

public port=62000\text{public port}=62000
Reply hits public portThe inbound and delivered tuples are decoded from exact bytes.Inbound reply tuple104 bits / 13 bytes0xc6336435cb007105110035f230byte 0byte 1byte 2byte 311000110001100110110010000110101byte 4byte 5byte 6byte 711001011000000000111000100000101byte 8byte 9byte 10byte 1100010001000000000011010111110010byte 1200110000source-ip198.51.100.53destination-ip203.0.113.5protocol17source-port53destination-port62000(cont.)Delivered tuple104 bits / 13 bytes0xc6336435c0a8010a1100359c40byte 0byte 1byte 2byte 311000110001100110110010000110101byte 4byte 5byte 6byte 711000000101010000000000100001010byte 8byte 9byte 10byte 1100010001000000000011010110011100byte 1201000000source-ip198.51.100.53destination-ip192.168.1.10protocol17source-port53destination-port40000(cont.)

The server is the source

The inbound source is server port 53.

server port=53\text{server port}=53
Reply hits public portThe inbound and delivered tuples are decoded from exact bytes.Inbound reply tuple104 bits / 13 bytes0xc6336435cb007105110035f230byte 0byte 1byte 2byte 311000110001100110110010000110101byte 4byte 5byte 6byte 711001011000000000111000100000101byte 8byte 9byte 10byte 1100010001000000000011010111110010byte 1200110000source-ip198.51.100.53destination-ip203.0.113.5protocol17source-port53destination-port62000(cont.)Delivered tuple104 bits / 13 bytes0xc6336435c0a8010a1100359c40byte 0byte 1byte 2byte 311000110001100110110010000110101byte 4byte 5byte 6byte 711000000101010000000000100001010byte 8byte 9byte 10byte 1100010001000000000011010110011100byte 1201000000source-ip198.51.100.53destination-ip192.168.1.10protocol17source-port53destination-port40000(cont.)

The tuple matches the saved row

Protocol 17 and public port 62000 match the saved mapping.

protocol=17\text{protocol}=17
Reply hits public portThe inbound and delivered tuples are decoded from exact bytes.Inbound reply tuple104 bits / 13 bytes0xc6336435cb007105110035f230byte 0byte 1byte 2byte 311000110001100110110010000110101byte 4byte 5byte 6byte 711001011000000000111000100000101byte 8byte 9byte 10byte 1100010001000000000011010111110010byte 1200110000source-ip198.51.100.53destination-ip203.0.113.5protocol17source-port53destination-port62000(cont.)Delivered tuple104 bits / 13 bytes0xc6336435c0a8010a1100359c40byte 0byte 1byte 2byte 311000110001100110110010000110101byte 4byte 5byte 6byte 711000000101010000000000100001010byte 8byte 9byte 10byte 1100010001000000000011010110011100byte 1201000000source-ip198.51.100.53destination-ip192.168.1.10protocol17source-port53destination-port40000(cont.)

Summary

The reply is recognized because it hits the saved public NAT endpoint.

inbound destination port=62000\text{inbound destination port}=62000
Reply hits public portThe inbound and delivered tuples are decoded from exact bytes.Inbound reply tuple104 bits / 13 bytes0xc6336435cb007105110035f230byte 0byte 1byte 2byte 311000110001100110110010000110101byte 4byte 5byte 6byte 711001011000000000111000100000101byte 8byte 9byte 10byte 1100010001000000000011010111110010byte 1200110000source-ip198.51.100.53destination-ip203.0.113.5protocol17source-port53destination-port62000(cont.)Delivered tuple104 bits / 13 bytes0xc6336435c0a8010a1100359c40byte 0byte 1byte 2byte 311000110001100110110010000110101byte 4byte 5byte 6byte 711000000101010000000000100001010byte 8byte 9byte 10byte 1100010001000000000011010110011100byte 1201000000source-ip198.51.100.53destination-ip192.168.1.10protocol17source-port53destination-port40000(cont.)