8

Today I heard that a customer can't send email to us. He received the following error:

< #5.5.0 smtp;550 [ipaddress] is not allowed to send mail from [domain name]. Please see http://www.openspf.net/Why?scope=mfrom;identity=name@domainname.com;ip=xxx.xx.xxx.xxx> #SMTP#

How is that possible? I searched the Internet for a possible solution, but I'm not sure what it is. When I go to openspf.net it seems like the records from the sender are wrong, but why is it that email to our company is blocked and email to other companies don't get blocked?

Is it possible that our domain is blocking the email with our spam filter? Or has it nothing to do with our own domain and does the sender have wrong records?

Peter Mortensen
  • 2,327
Jordy
  • 255

1 Answers1

13

If it's being blocked due to an SPF record, then ideally they need to correct their SPF records to include their sending MX hosts.

The reason it will be blocked by your mail servers and not others is purely down the configuration of mail servers or relays in your organisation to honor SPF records of the sender. Other organisations chose not to honor SPF.

If I'm ever in the same position as you, I would normally temporarily whitelist the sender (if that's possible on your mail server/mail relay/spam filters) so it avoids the SPF check if required, and encourage them to change their SPF records.

Alex
  • 146
  • 1
  • 2