Method and system for optimizing and preventing failure of sender policy framework (SPF) lookups

• US 10,447,633 B2
• Filed: 09/26/2016
• Issued: 10/15/2019
• Est. Priority Date: 09/25/2015
• Status: Active Grant

• Current Assignee: Amit Gupta
• Original Assignee: Amit Gupta
• Inventors: Gupta, Amit
• Primary Examiner(s): Khan, Atta
• Application Number:
  US15/275,744
• Publication Number:
  US 20170093772A1
• Time in Patent Office: 1,114 Days
• Field of Search: 709206
• CPC Class Codes: H04L 2101/35 containing special prefixes
• CPC Class Codes: H04L 51/04 Real-time or near real-time messaging, e.g. instant messaging [IM]
• CPC Class Codes: H04L 51/212 using filtering or selective blocking
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• CPC Class Codes: H04L 67/56 Provisioning of proxy services store-and-forward switching systems in data switching networks H04L12/54
• CPC Class Codes: H04L 67/566 Grouping or aggregating service requests, e.g. for unified processing

Abstract

The present invention circumvents the standard SPF lookup limit by allowing an administrator to create a secondary SPF record that includes all the desired SPF records even if it exceeds the 10 recursive lookups that would result in a standard failure. The administrator would then then create or modify their main SPF record to include an entry that points to the SPF Proxy that is the subject of this invention.

Claims

1. A method for optimizing and preventing failure of sender policy framework (SPF) lookups recorded on non-transitory computer-readable medium and capable of execution by a computer, the method comprising the steps of:

requesting a regular SPF Record;

receiving a SPF Record that points to a Proxy Server (SPF Proxy Record);

conditionally checking a Proxy DNS entry based on merged SPF Macros;

performing an SPF authentication check based on a conditionally received DNS record; and

returning a Synthetic SPF response that incorporates the results of the SPF authentication check in a format that adheres to the SPF standard and whose result would match the SPF authentication check result even without DNS lookup limits;

responding with the same Synthetic SPF response regardless of EHLO or IP information;

the Synthetic SPF response contains a single block of IPs or a single included SPF entry;

the Synthetic SPF response contains a single included SPF “

exists”

entry or “

redirect”

entry;

the Synthetic SPF response is the same across all requests; and

the Synthetic SPF response includes a chain of include entries if the synthetic record exceeds the size of a record based on the SPF protocol specification.

2. The method of claim 1, further comprising the step of:

changing the required behavior of the SPF authentication check by increasing a DNS lookup limit;

not varying the Synthetic SPF response; and

returning a flattened list of authorized networks.

3. The method of claim 1, further comprising the step of:

using a cached response from a previous lookup that matches completely.

4. A method for optimizing and preventing failure of sender policy framework (SPF) lookups recorded on non-transitory computer-readable medium and capable of execution by a computer, the method comprising the steps of:

sending an email from a mail server;

the email contains one or more properties that will be used for one or more SPF Macros;

attempting to do an SPF validation using email domain'"'"'s SPF record;

making a DNS request;

responding with an SPF Proxy Record;

processing the SPF Macros in a returned Proxy Record;

generating a DNS TXT request to the domain'"'"'s SPF proxy;

receiving the DNS TXT request and extracts a merged macro;

looking up a Canonical SPF Record from the email domain'"'"'s DNS server by making a request;

conducting a standard SPF validation; and

constructing a synthetic response record based on the results from the standard SPF validation;

responding with the same constructed synthetic response record regardless of EHLO or IP information;

the synthetic response record contains a single block of IPs or a single included SPF entry;

the synthetic response record contains a single included SPF “

exists”

entry or “

redirect”

entry;

the synthetic response record is the same across all requests; and

the synthetic response record includes a chain of include entries if the synthetic response record exceeds the size of a record based on the SPF protocol specification.

5. The method of claim 4, wherein the email is from an actual mail server for the domain or a third party email provider.

6. The method of claim 4, wherein

the Canonical SPF record is determined by an optional or required “

selector”

contained within the proxy record; and

the email domain'"'"'s SPF records are static.