I'm completely new to Stack Overflow, so Hi!

I need to add an SPF record to my site "main.com" (not the real address) to allow an email publishing company "emailpublishers.com" (not the real address) to send emails on my behalf. However, I'm nervous about adding an SPF record because of the havoc it could wreak if done incorrectly.

I use Google Apps. I also use "auxiliary.com" to send mail from "main.com." And, of course, I use "main.com" to send mail as well. "auxiliary.com" doesn't have an SPF record.

I used Microsofts' and OpenSPF's wizards to generate the following SPF entry. Does it seem to be correct for me?

"v=spf1 a mx ip4:55.55.555.55 mx:alt1.aspmx.l.google.com mx:alt2.aspmx.l.google.com mx:aspmx.l.google.com mx:aspmx2.googlemail.com mx:aspmx3.googlemail.com mx:aspmx4.googlemail.com mx:aspmx5.googlemail.com a:auxiliary.com include:_spf.google.com include:auxiliary.com mx:auxiliary.com include:emailpublishers.com mx:emailpublishers.com ~all"

However, my host MediaTemple says in a knowledge base article to use:

v=spf1 a:main.com/20 ~all

So that added to my confusion.

Thanks a lot!