METHODS AND SYSTEMS FOR SECURELY DELIVERING ELECTRONIC MAIL TO HOSTS HAVING DYNAMIC IP ADDRESSES

• US 20020004826A1
• Filed: 09/15/1998
• Published: 01/10/2002
• Est. Priority Date: 09/15/1998
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: WAITE, RYAN W. J., LAMBERT, BRUNO
• Granted Patent: US 6,434,600 B2
• Time in Patent Office: Days
• US Class Current: 709/223
• CPC Class Codes: H04L 51/48 Message addressing, e.g. address format or anonymous messages, aliases
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• CPC Class Codes: H04L 61/4552 Lookup mechanisms between a plurality of directories; Synchronisation of directories, e.g. metadirectories
• CPC Class Codes: H04L 61/5076 Update or notification mechanisms, e.g. DynDNS

Abstract

The present invention includes methods and systems for securely delivering electronic mail to electronic mail servers having dynamic IP addresses. Before requesting mail delivery, a receiving mail server having a dynamic IP address registers its dynamic IP address along with a receiving mail server code in memory accessible by a dynamic name server. The receiving mail server code is preferably also stored with the domain name for which the receiving mail server receives mail in memory accessible by a private name server. In response to a request for mail delivery, a delivering mail server utilizes the receiving mail server code stored in memory accessible by the private name server and the dynamic name server to determine the dynamic IP address.

Claims

1. A method for securely delivering electronic mail to a mail server having a dynamic IP address comprising:

registering a dynamic IP address and a receiving mail server code of a receiving mail server with a dynamic name server;

transmitting a request for delivery of electronic mail from the receiving mail server to a delivering mail server;

transmitting a request for the dynamic IP address from the delivering mail server to a private name server;

transmitting a request for determining the dynamic IP address from the private name server to the dynamic name server, the request including the receiving mail server code;

extracting the dynamic IP address from the dynamic name server based on the receiving mail server code;

transmitting the dynamic IP address to the delivering mail server; and

delivering electronic mail from the delivering mail server to the receiving mail server utilizing the dynamic IP address extracted from the dynamic name server.

2. The method of claim 1 wherein registering a dynamic IP address and a receiving mail server code comprises:

allocating memory for an A record having a Resource Domain Name field and an IP address field;

storing the receiving mail server code in the Resource Domain Name field; and

storing the dynamic IP address in the IP address field.

3. The method of claim 1 comprising, before transmitting the request for delivery of electronic mail, storing the dynamic IP address of the receiving mail server and the receiving mail server code in the private name server.

4. The method of claim 3 wherein storing the IP address and the receiving mail server code in the private name server comprises:

allocating memory for an MX record having an Exchange-Dname field and a Resource Domain field;

storing the receiving mail server code in the Exchange-Dname field; and

storing a domain name for which the receiving mail server receives mail in the Resource Domain Name field.

5. The method of claim 4 wherein transmitting a request for the dynamic IP address from the delivering mail server to the private name server comprises:

transmitting a request for the MX record from the delivering mail server to the private name server;

extracting the MX record from the private name server;

transmitting the MX record from the private name server to the delivering mail server; and

transmitting a request for the A record from the delivering mail server to the private name server.

6. The method of claim 1 wherein transmitting a request for delivery of electronic mail comprises transmitting an SMTP ETRN command from the receiving mail server to the delivering mail server.

7. The method of claim 1 wherein registering a dynamic IP address and a receiving mail server code comprises registering a dynamic IP address and a secret receiving mail server code with the dynamic name server.

8. The method of claim 7 wherein registering a dynamic IP address and a secret receiving mail server code comprises transmitting a name registration request including the dynamic IP address and the secret receiving mail server code to a WINS server.

9. A system for securely delivering electronic mail to electronic mail servers having dynamic IP addresses comprising:

a delivering mail server for receiving requests for electronic mail delivery from a plurality of receiving mail servers having dynamic IP addresses via a network and for delivering electronic mail to the plurality of receiving mail servers;

a dynamic name server for receiving and storing receiving mail server codes and corresponding dynamic IP addresses of the receiving mail servers; and

a private name server in communication with the dynamic name server and the delivering mail server for storing the receiving mail server codes and corresponding domain names of the plurality of receiving mail servers, wherein the private name server accesses the dynamic name server to determine dynamic IP addresses of the plurality of receiving mail servers.

10. The system of claim 9 wherein the dynamic name server comprises a WINS server.

11. The system of claim 9 wherein the dynamic name server comprises a dynamic DNS server.

12. The system of claim 9 wherein the private name server comprises a DNS server.

13. The system of claim 9 wherein the delivering mail server comprises an SMTP server.

14. The system of claim 9 wherein the dynamic name server stores a plurality of A records having Resource Domain Name fields and IP address fields, wherein the receiving mail server codes are stored in the Resource Domain Name fields and the dynamic IP addresses are stored in the IP address fields.

15. The system of claim 9 wherein the private name server stores a plurality of MX records having Exchange-Dname fields and Resource Domain Name fields, wherein the receiving mail server codes are stored in the Exchange-Dname fields and domain names for which the plurality of receiving mail servers receive mail are stored in the Resource Domain Name fields.

16. The system of claim 9 wherein the plurality of receiving mail server codes are secret codes.

17. A method for securely communicating a dynamic IP address of a receiving mail server to a delivering mail server comprising:

registering a dynamic IP address and a receiving mail server code of a receiving mail server with a dynamic name server; and

in response to a request for the dynamic IP address of the receiving mail server transmitted from a delivering mail server to a private name server;

searching resource records in the private name server for a record containing the dynamic IP address,

transmitting a request for the dynamic IP address from the private name server to the dynamic name server, the request including the receiving mail server code,

extracting the dynamic IP address from the dynamic name server based on the receiving mail server code, and

transmitting the dynamic IP address to the delivering mail server.

18. The method of claim 17 wherein registering a dynamic IP address and a receiving mail server code comprises:

allocating memory for an A record having a Resource Domain Name field and an IP address field;

storing the receiving mail server code in the Resource Domain Name field; and

storing the dynamic IP address in the IP address field; and

transmitting a name registration request including the A record from the receiving mail server to the dynamic name server.

19. The method of claim 17 further comprising storing the receiving mail server code and a domain name of the receiving mail server with the private name server.

20. The method of claim 19 wherein storing the receiving mail server code and a domain name of the receiving mail server comprises:

allocating memory for an MX record having a Resource Domain Name field and an Exchange-Dname field;

storing the receiving mail server code in the Exchange-Dname field; and

storing the domain name of the receiving mail server in the Resource Domain Name field.

21. The method of claim 17 further comprising generating the receiving mail server code and storing the receiving mail server code in the receiving mail server.

22. The method of claim 17 wherein registering a dynamic IP address and a receiving mail server code comprises registering a dynamic IP address and a secret receiving mail server code with the dynamic name server.

23. A computer-readable medium having computer-executable instructions for performing steps comprising:

(a) identifying a routeable dynamic IP address received from a network; and

(b) registering a receiving mail server code and the dynamic IP address with a dynamic name server.

24. The computer-readable medium of claim 23 having computer executable instructions for performing steps further comprising after step (b),

(c) requesting delivery of electronic mail from a delivering mail server;

and

(d) receiving electronic mail routed to the dynamic IP address from the delivering mail server.

25. The computer-readable medium according to claim 23 wherein step (b) comprises:

allocating memory for an A record having a Resource Domain Name field and an IP address field;

storing the receiving mail server code in the Resource Domain Name field; and

storing the dynamic IP address in the IP address field; and

transmitting a name registration request including the A record from the receiving mail server to the dynamic name server.

26. The computer-readable medium of claim 24 comprising, after step (d), unregistering the receiving mail server code and the dynamic IP address from the dynamic name server.

27. A computer-readable medium having stored thereon a data structure, the data structure including an A record comprising:

(a) a first data field containing data representing a receiving mail server code of a receiving mail server; and

(b) a second data field containing data representing a dynamic IP address of the receiving mail server.

28. The computer-readable medium of claim 27 wherein the first data field comprises a Resource Domain Name Field and the second data field comprises an IP Address field.

29. A computer-readable medium having stored thereon a data structure, the data structure including an MX record comprising:

(a) a first data field containing data representing a receiving mail server code of a receiving mail server; and

(b) a second data field containing data representing a domain name of a domain for which the receiving mail server receives mail.

30. The computer-readable medium of claim 29 wherein the first data field comprises an Exchange-Dname field and the second data field comprises a Resource Domain Name field.