If I am receiving a yahoo e-mail from two different users - apparently two different states, how could they both have the exact identical ip address, including the last 3 digits? Makes no sense. To me, they are the same people. Please let me know if the same exact i.p. address, including the last 3 digits, are from the same person.
Emails are not sent to your computer directly from a person's PC. If they were, then I would answer this question "they're using a VPN".
But since emails are routed through an email server, then this makes a lot of sense.
The person sending email to you sends their message, which is then picked up by their email provider that has an address of 123.456.789.100 and sends it along to you. Another person sends an email who is using the same provider, therefore the same IP address for the server.
You're seeing the email server's IP. Online email service providers don't let you see the origin IP address of the machine the email was sent from, unless you're a powerful government organization with handy pieces of unlawful legislation...
You need to understand that your computers (persons, as you call them) can have the same IP address, though not necessarily at the same time, if they accessing the Internet via a dial-up ISP that gives these users dynamic IP addresses, but usually within same subnet
- Computer A connects to the Internet, and the IP address will continually vary around 192.168.12.xxx during a browsing session
- Computer B with same provider does same, and same thing happens
BUT: No one will have same IP address at the same time
So, it's possible for you to receive an email from two different persons with same IP address (at different times)
But that is just one possibility! @Moses' answer is another!