FACILITATING TRANSMISSION OF EMAIL BY CHECKING EMAIL PARAMETERS WITH A DATABASE OF WELL BEHAVED SENDERS

• US 20100005146A1
• Filed: 07/03/2008
• Published: 01/07/2010
• Est. Priority Date: 07/03/2008
• Status: Active Grant

• Current Assignee: Barracuda Networks Incorporated
• Original Assignee: Barracuda Networks Incorporated
• Inventors: LEVOW, ZACHARY, DRAKO, DEAN
• Granted Patent: US 7,996,475 B2
• Time in Patent Office: Days
• US Class Current: 709/206
• CPC Class Codes: G06Q 10/00 Administration; Management
• CPC Class Codes: G06Q 10/107 Computer-aided management of electronic mailing [e-mailing]
• CPC Class Codes: H04L 51/00 User-to-user messaging in packet-switching networks, transmitted according to store-and-forward or real-time protocols, e.g. e-mail
• CPC Class Codes: H04L 51/212 using filtering or selective blocking
• CPC Class Codes: H04L 51/48 Message addressing, e.g. address format or anonymous messages, aliases

Abstract

Facilitating email transmission by extracting email parameters, requesting data in the form of a dns query, and receiving a sender reputation as an IP address. Querying a database by sending a plurality of arguments concatenated to a dns request and receiving an IP address in reply. Operating a remote database as a dns server, receiving queries as domains and transmitting replies in the format of IPv4 or IPv6 addresses. Filtering email by querying a database with email parameters comprising an IP address and a domain of an email sender which may be extracted from an email header in the HELO, EHLO, MAIL FROM, or RETURN PATH. The smtp session is continued, modified or interrupted according to the result of the query submitted to a database operating as a dns server.

Claims

1. A method comprising the steps of

determining email parameters for an email wherein email parameters comprise a domain name and an IP address;

looking up the email parameters in a database; and

if the email parameters are found, facilitating email delivery.

2. The method of claim 1 wherein looking up the email parameters comprise composing a fully qualified domain name by concatenating the email parameters with the domain operating the database and querying the domain name system.

3. The method of claim 1 wherein facilitating email delivery comprises skipping spam scanning if the email parameters are found in the database.

4. The method of claim 1 further comprising concatenating an authentication code into the fully qualified domain name to show authorized access to the database.

5. The method of claim 1 further comprising receiving a reply from the database in the form of text or IP address whereby some variable information about the email parameters is encoded within the text or IP address.

6. A method comprising the steps of

determining email parameters for an email wherein email parameters comprise a domain name and an IP address;

looking up the email parameters in a database; and

if the email parameters are found, facilitating email delivery, wherein looking up the email parameters comprise composing a fully qualified domain name by concatenating the email parameters with the domain operating the database and querying the domain name system.

7. The method of claim 6 wherein facilitating email delivery comprises skipping spam scanning if the email parameters are found in the database.

8. The method of claim 6 further comprising concatenating an authentication code into the fully qualified domain name to show authorized access to the database.

9. The method of claim 6 further comprising receiving a reply from the database in the form of text or IP address whereby some variable information about the email parameters is encoded within the text or IP address.

10. A method for facilitating email delivery comprising

extracting email parameters from header and body of a tcp packet,

querying a dns resolver with a fully qualified domain name,

receiving a reply, and

processing the email according to the reply.

11. A method for facilitating email delivery comprising

extracting email parameters,

querying a database,

receiving a reply, and

blocking the email from propagation when the email parameters match those of a spammer.

12. A method for facilitating email delivery comprising

extracting email parameters,

querying a database, receiving a reply, and

setting a score on the email for further analysis when the email parameters do not match those of a sender without a history of sending spam.

13. A method for facilitating email delivery comprising

extracting email parameters,

querying a database,

receiving a reply, and

bypassing any additional filtering whereby email is transmitted to the recipient when the email parameters match that of a sender without a history of sending spam.

14. A method for querying a database comprising the following steps:

sending a dns request of class=IN to a dns server;

concatenating a suffix of the domain of the database to a plurality of query arguments to

form a string formatted as a fully qualified domain name,

sending dns queryname=the fully qualified domain name; and

receiving data as a dns query response from a dns query server,

wherein a fully qualified domain name comprises a plurality of labels separated by dots and ending with a domain, a dot and a top level domain, wherein a first query argument is a domain of an email sender and a second query argument is a hostid of an email sender wherein a hostid is an IP address and wherein the dns request type is selected from the group A, AAAA, TXT, CNAME, and SPF.

15. The method of claim 14 wherein the data represents one of a subjective probability of spam on a scale, an action suggested, and a degree of filtering.

16. A method for filtering email between an smtp client and an smtp server wherein smtp is simple mail transfer protocol, the method comprising

forming at least one set of email parameters from an smtp session,

querying a server before completing the smtp session, and

facilitating transmission of the email according to the reply from the reputation server.

17. A method for forming a set of email parameters from an smtp session comprising the steps of extracting a sender email address from an smtp mail command and extracting a smtp client IP address from an IP header of the smtp mail command.

18. A method for forming a set of email parameters from an smtp session comprising the steps of extracting a smtp client domain from an smtp EHLO or HELO command and extracting an smtp client IP address from an IP header of the smtp EHLO or HELO command.

19. The method of claim 18 wherein the data comprises a first IP address if there is a match and a second IP address if there is not a match within the database server.

20. The method of claim 18 wherein querying a database comprises appending a certain suffix to a string and querying a domain name system wherein a string comprises at least two email parameters concatenated in any order, wherein email parameters are selected from the following:

a domain, an IP address, and a local-part of an email address.

21. The method of claim 18 wherein email parameters comprise at least two of the IP ADDRESS from a connect, the IP ADDRESS from an SMTP packet, the FROM argument of an envelope, message body, message envelope, HELO command, EHLO command, and a return-path, and the return-path, mail-from of an email body, and the domain name argument of EHLO and domain name argument of HELO.

22. A method comprising formulating a fully qualified domain name (FQDN) by concatenating a plurality of arguments to a host name, said host name associated with a service, sending a domain name system query from a resolver, receiving a domain name system query from the resolver, operating a service by inputting a plurality of arguments, formulating a reply encoded as text or an IP address wherein said IP address may be IPv4 or IPv6 format, transmitting said reply to said resolver, receiving said reply, and at least one of the following, facilitating transmitting an email to a recipient, blocking an email from transmission to a recipient, concluding a transaction, closing a session, acknowledging a request, displaying a message or image associated with said reply IP address, enabling software based on said reply IP address, licensing use of intellectual property based on said reply IP address, releasing a controlled physical matter based on said reply IP address, and providing a service based on said reply IP address.

23. The system of claim 22 wherein an argument comprises one of a local part of an email address, an email domain, a text string following an “

at”

sign, a top level domain concatenated to a hostname, a text string extracted from the argument of a MAIL from command, a text string extracted from a “

return-path”

value, a text string extracted from a MAIL FROM field in a mail body, and a top level domain of an email sender and the label to the left of the top level domain.

24. The system of claim 22 wherein an argument comprises one of an IP address from a TCP packet, an IP address associated with an TCP connect, an IP address associated with an SMTP command, an IP address associated with an email header, an IP address associated with a UDP session, an IP address associated with a telnet session, and an IP address associated with an Internet Engineering Task Force request for comment protocol.

25. A method for facilitating delivery of email comprising the steps of accumulating a database of email parameters of senders of non-spam email;

operating a service as a domain name system server on a host;

extracting email parameters from an SMTP session operating on TCP;

appending a plurality of email parameters to the hostname of the service;

querying a domain name system resolver;

receiving reply from the domain name system server, and

delivering the email to the recipient if the email parameters are found in the database, else disposing of the email if the email parameters are not found in the database.

26. The method of claim 25 wherein email parameters for an email comprise a domain name and an IP address extracted from the TCP packet and wherein the IP address within the body of the email is ignored.

27. The method of claim 25 wherein querying a domain name resolver comprise composing a fully qualified domain name by concatenating the email parameters with the hostname of the host operating the database as a service and querying the domain name system.

28. The method of claim 25 wherein the reply from the domain name system server is formatted as an IP address but is not an IP address and represents a code.

29. The method of claim 25 wherein delivering the email to the recipient comprises bypassing email filtering processes and forwarding the email to the recipients mail server.

30. The method of claim 25 wherein disposing of the email comprises at least one selected from the following processes:

terminating the SMTP session, transferring the email to a spam scanner, transferring the email to a folder, messaging the recipient, forwarding the email to an archive, and modifying the email with a flag or warning and storing it.