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--- mail_servers [2015/06/01 16:52]
steve
+++ mail_servers [2018/10/18 02:17]
steve
@@ Line 21: / Line 21: @@
 SPF records are DNS ''TXT'' records that verify that the server that is sending outgoing email from your domain name is authorized.
-As an example, here is an ''@'' ''TXT'' entry for Digital Trike that allows A2 Hosting (75.98.175.91) and GMail (_spf.google.com):
+Here's a basic example where any email sent out from the domain's A record is authorized. Otherwise, do a hard fail.
+Using as an example, ''beandog.org'':
+<code>
+v=spf1 a -all
+</code>
+Authorize only servers that have MX entries in DNS (such as mail.beandog.org), or in other words, for mail servers that receive incoming mail for that domain:
+<code>
+v=spf1 mx -all
+</code>
+Find the current MX servers using dig:
 <code>
-v=spf1 a mx ip4:75.98.175.91 include:_spf.google.com ~all
+dig +short mx beandog.org
+mail.beandog.org.
 </code>
-If you want to add multiple IP addresses, then add an extra ''ip4:'' rule to the existing record:
+Allow a specific IP address to send mail:
 <code>
-v=spf1 a mx ip4:75.98.175.91 ip4:12.34.56.78 include:_spf.google.com ~all
+v=spf1 ip4:208.111.40.179 -all
 </code>
@@ Line 42: / Line 57: @@
 <code>
-echo testing email | mail -r website@digitaltrike.com -s testing [mail-checker address]
+echo testing email | mail -r website@domain.com -s testing [mail-checker address]
 </code>