Gmail requires SPF record

When I send emails from my domain to multiple gmail address and others, all the others get delivered. After three days, my host server sends me an email saying all gmail addresses were rejected.

“A message that you sent could not be delivered to one or more of its recipients. This is a permanent error.  The following address(es) failed:  {followed by all the itemized gmail addresses}”

This needs to get fixed!  Calling my ISP (1and1) was great. They immediately recognized the problem and suggested a fix.  Turns out gmail has decided to reject emails to multiple gmail addresses unless they can find a special SPF record associated with the email sender domain that authorize the IP address of the email sender.

TXT v=spf1 mx a ptr ~all

See http://www.openspf.org/SPF_Record_Syntax to interpret that syntax:

• We’re using SPF version 1.0
• All the mx records are checked to see if the sender IP is found
• The a records are checked to see if the sender IP is found
• PTR hostname lookups are checked to see if the client IP is found
• If the sender IP is not yet matched, spf returns a softfail for all other queries

The text above is what my ISP says gmail requires. I wonder… if I could add an implied “+” in front of the mx and a and ptr for readability. I’d also like to add +ip4:10.0.0.1/24 so that email from my laptop will be accepted, however, I’m not sure that is necessary because from gmail’s perspective, the email comes from a 1and1 server, not my local laptop IP address.