Recently I was attempting to open a Paypal account for my company. No problem doing that or at least there should not have been.

I created an account and was waiting for the confirmation email to come through from Paypal to confirm the email address but it never arrived, so I tried requesting it again and still no sign. So before attempting to contact Paypal I looked through the log files on the companies email server to see if it had arrived at the server. The companies email server runs Qmail on Linux, and there was signs of it having arrived but then a strange status 11 message in the qmail-smtpd logs.

After much searching on the Internet for ideas I finally found the problem.

The Qmail installation on the companies email server has the SPF patch incorporated and enabled, look at www.openspf.org if you want to find out more about SPF. I discovered a patch here http://qmail.jms1.net/patches/combined-details.shtml to fix a problem in the SPF patch which causes qmail-smtpd, the program that receives email to seg fault (crash) and return a status 11 return value on some installations, when it receives email from a sender who has a large SPF record, Paypal have a large SPF record.

To prove this was the problem I simply turned off SPF checking on our email server by putting 0 in the file spfbehaviour in the Qmail control directory. I then requested the verification email from Paypal again and through it came no problem. I also realised that I had not been receiving Paypal payment notifications for my personal account for quite a while, with hindsight since SPF was enabled on the email server, and they have started coming through again as well now.

So now I need to recompile our Qmail server with the updated SPF patch.