Multiple SPF records for a single domain might result in inconsistent SPF policies and SPF record syntax problems, which can affect email deliverability. As a result, it's crucial to make sure that a single SPF record has information from all pertinent sources.
If a domain needs more than one SPF entry, they must all be consolidated into one record with a maximum character count of 255.
List all the sources using their techniques, such as "a," "mx," "include," "ip4," etc., to add many sources to an SPF record. It is advised to create subdomains for particular email flows and put up distinct SPF records for each subdomain if the record is longer than the allotted 255 characters.
The SPF records have a search limit of 10, though, and this is something that must be kept in mind. If a domain goes over this limit, some sources could not be recognized, which could cause problems with email delivery. Reduce the number of lookups to prevent this by getting rid of any redundant techniques and checking that the included domains are current. Additionally, a cutting-edge method that can assist cut down on lookups is the use of SPF macros.
DNS delegation can be used to fix the problem if a domain still receives an excessive number of lookups. The SPF delegation tool offers an alternative policy that can take the place of the current policy and will update the SPF record whenever any included ESPs modify their records. In order to determine the quantity of lookups contained in a particular SPF record, it is advised to use an SPF record checker.