Relevant Products: Exclaimer Cloud - Signatures for Office 365 | Exclaimer Cloud - Signatures for G Suite
Sender Policy Framework (SPF) is a protocol used to prevent spammers from sending messages with forged ‘From’ addresses at your domain.
An SPF record is a type of TXT record which identifies any mail servers permitted to send email on behalf of your domain; they are also known as Reverse MX records.
Domain administrators publish SPF records in the Domain Name System (DNS); this enables the incoming mail servers to verify the domain name from which email messages are sent. When a recipient's mail server receives an email message, it checks the SPF record to determine whether it is a valid message. If the message comes from a server that is included in the SPF record, it is legitimate; if not, it is rejected as spam.
Do I have to update the SPF records?
Yes, we recommend you update the SPF records to include the Exclaimer SPF record. This will ensure that your emails are delivered when they are transported through our service.
How to update the SPF records?
The exact process varies from one service provider to another; generally, it involves adding one line to a DNS TXT record.
You, as an IT Administrator, need to update the SPF records based on the Exclaimer Simple Mail Transfer Protocol (SMTP) hosts.
Warning: Make sure you are aware of your region code before you update the SPF records. You need to enter the 'region code' for the SPF records to update successfully:
UK United Kingdom
US United States
Can I have multiple SPF records?
Multiple SPF records are not recommended as this can cause issues with delivery and/or spam classification.
Domain Name System (DNS), is a system that is used to identify and organise Web domains.
It is similar to a telephone directory for the Web, which allows network communication services to look up names and translate them into Internet Protocol (IP) addresses.
DNS information is gathered from all the domain name servers across the Internet and stored at the Central Registry. Hosting companies and Internet Service providers interact with this registry on a regular basis to obtain the updated DNS information.
So, when you type 'www.exclaimer.net' into a web browser, DNS looks up for this address and establishes which IP address should be used to make a connection then it displays the web page.
For emails, it's a little bit complicated if you start to look at how an email is sent and received. We'll have to dig deep and look at DNS records. Although, DNS includes different types of records for specific purposes, for this article, we are discussing two particular types of records: mail exchanger (MX) and text (TXT).
- mail exchanger record (MX) are resource records within the DNS which specify a mail server responsible for accepting email messages on behalf of a recipient's domain, together with a preference value which is used to prioritise delivery if multiple mail servers are available. All domains publish MX records so we know which servers can receive email for the domain. So, when an email is sent, the sending mail server looks up for the MX record in the DNS to obtain the relevant IP address.
- text record (TXT) is a DNS record that provides text information to sources outside your domain; it can be used for many different purposes, one of which is Sender Policy Framework (SPF). So, when we refer to SPF records, we are referring to a particular type of TXT record within the DNS.