I used some hacker knowledge I learned in the software development process.

In the LAN, two machines are used as email servers, one is you. Mail and the other is my. Mail. They want their users to send emails to each other. For example, the mail users on you. Mail can send emails to the mail users on my. Mail. Because we are in the LAN, the names you. Mail and my. Mail are random and we didn't really apply for a domain name. If it is normal, it is impossible to transfer the domain name, because after the DNS, the two domain names cannot be found.

As a result, I naturally think of address spoofing, a little thing I learned when I learned about network security. Through address spoofing, the email is sent directly to the destination address instead of through DNS during transmission. In this way, the problem is simply solved.

I was surprised and happy to learn a little hacker knowledge during software development.