×

System and method for protecting mail servers from mail flood attacks

  • US 8,180,835 B1
  • Filed: 10/14/2006
  • Issued: 05/15/2012
  • Est. Priority Date: 10/14/2006
  • Status: Expired due to Fees
First Claim
Patent Images

1. A system for controlling electronic mail flood attacks comprising:

  • a network interface;

    a suspicious address class in a set of suspicious address classes;

    a counter associated with the suspicious address class, wherein the counter counts active connections originating from the suspicious address class to the network interface;

    an SMTP handler configured to process electronic mail messages, wherein whenever the SMTP handler receives an email request from the suspicious address class and at least one of a set of at least one failure criteria is met, the SMTP hander issues a temporary failure message, wherein the set of at least one failure criteria comprises a first criterion which is met when the counter has reached a predetermined limit;

    a first timer, wherein the first timer is restarted whenever the counter falls below the predetermined limit and expires after a first predetermined interval, wherein the set of at least one failure criteria further comprises a second criterion which is met when the first timer has been restarted and has not expired; and

    a second timer, wherein whenever any one of the set of at least one failure criteria has been met by a previous email request originating from the suspicious address class, the second timer is restarted and expires after a second predetermined interval, wherein the set of at least one failure criteria further comprises a third criterion which is met when the second timer has been restarted and has not expired.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×