Chapter 19 NAT

SMTP server replied directly to the LAN user without the traffic going through NAT, the source would not match the original destination address which would cause the LAN user’s computer to shut down the session.

Figure 295 LAN to LAN Return Traffic

NAT

Source 192.168.1.21

Source 1.1.1.1

 

SMTP

 

 

SMTP

 

LAN

192.168.1.21192.168.1.89

 

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