SPF Guide

1. What is SPF?

Answer: SPF stands for Sender Policy Framework. SPF is an email authentication standard used to prevent email fraud and spam. It ensures the authenticity and reliability of email by verifying that the sender's domain name matches the source IP address of the email. SPF records are stored in the DNS record of the domain name and contain a list of servers that are allowed to send emails. When the recipient receives an email, it checks whether the sender's domain name has an SPF record and verifies whether the IP address of the sending server is in the allowed list. If the verification fails, the recipient may mark the email as spam or refuse to receive it. Using SPF can help improve the delivery rate and reliability of emails and reduce the amount of spam. At the same time, it can also enhance the security of the email system and prevent hackers and fraudsters from using forged domain names to send emails.

2. How to set up SPF for corporate mailboxes?

Answer:

1. Determine the outgoing server IP addresses of your corporate mailbox: These addresses will be added to the SPF record. 2. Log in to the DNS management console of your corporate mailbox: Usually provided by your domain name registrar or hosting provider

2. Create or edit a TXT record: In the DNS console, find the TXT record or similar option

3. Enter the SPF record: The format of the SPF record is "v=spf1 +a/+mx +ip4 +ip4:mail.example.com -all", where:

"v=spf1": specifies the SPF version

"a" or "mx": indicates that the server is allowed to be verified by the A record or MX record

"ip4": lists the IP addresses that are allowed to send mail

"mail.coremail.cn": replaced with the domain name of your corporate mailbox

"-all": indicates that mail from all other sources is rejected

4. Save changes: Make sure the settings in the DNS console are saved correctly

3. How to set various types of SPF?

1) Make SPF record with domain name a record (take coremail.cn as an example)

v=spf1 a:coremail.cn2 -all

2) Make SPF record with domain name mx record

v=spf1 mx -all

3) Make SPF record with domain name ptr record

v=spf1 ptr -all

4) Make SPF record with export IP and IP segment settings

v=spf1 ip4:106.52.172.248 ip4:61.164.47.194/28 -all

5) Introduce SPF records of other domain names (take spf.icoremail.net as an example)

v=spf1 include:spf.icoremail.net

Note: The above records can be used in combination, but only one pair of records starting with v=spf1 and ending with -all can appear in the entire txt. For example: v=spf1 mx ip4:106.52.172.248 include:spf.icoremail.net -all