How To Use SPF Lookup Counter For Determining The Number Of Lookup Counts
Every SPF implementation must limit the number of modifiers and mechanisms for doing SPF lookups to at most 10. Users who do not follow this limit get permerror SPF permanent error too many DNS lookups. To avoid the SPF lookup failure, they can use techniques like SPF flattening, multiple SPF records, SPF compression, etc., but it is best to know the number of counts to avoid the SPF lookup limit.
SPF Lookup Counter: How To Determine The Number Of Counts?
Let us take the example of SPF records that Google publishes for its customers. The users must include the _spf.google.com SPF record in their domain SPF records. When you do an SPF lookup of the record in DNS, you will find:
v=spf1 include:_sampledomain.google.com include:_sampledomain2.google.com include:_sampledomain3.google.com ~all
Each of the included _sampledomain SPF records contains a list of IP addresses and doesn’t require additional domain lookups. Now suppose a domain only includes the record recommended by Google:
include:_spf.google.com ~all
It will have a lookup count of four – one each for previously mentioned records and one for _spf.google.com lookup. Now suppose you wish to add the SPF records provided by other mail service providers. The SPF lookup counter can be calculated in the manner we discussed with the _spf.google.com. The total count will be the sum of individual contributions. For example, if mailprovider.com contains three additional domains in its records, then the following record will have a total domain lookup count of 8.
v=spf1 include:_spf.google.com include:mailprovider.com ~all
While there are other methods to avoid the typical SPF too many DNS lookups errors, it is safe to use the SPF lookup counter to determine the number of counts in advance. It’s better to be safe than sorry!
Join the thousands of organizations that use DuoCircle
Find out how affordable it is for your organization today and be pleasantly surprised.