2.3 Two email servers

Given the previous scenario, neither Comcast nor Surewest wants to own that server. If Comcast owns that server, then it is serving Jennifer for free. If Surewest owns that server, then it is serving John for free.

The solution is actually quite simple. Comcast has its email server, and Surewest has its own. This is what happens, then:

• John sends the message, it is transmitted to Comcast’s email server.
• Comcast’s email server analyzes the recipient’s address. Then it relays the message to Surewest’s email server.
• Surewest’s email server stores the message.
• When Jennifer logs in, the message is read or delivered from Surewest’s email server.

Now, both companies are happy because they only serve their own customers.