Putting this out there in case it helps someone else.  My Google results on this didn't yield any direct hits.I needed a cheap replacement email host, and picked 1and1.com.  I rapidly found that 1and1 doesn't use SPF in their DNS, but luckily I already maintain my own DNS records.  Great right?  Kinda. They don't document their outbound servers to populate your SPF settings so you have to hunt it down...  1and1's article on the subject: What are SPF Records?
1and1.com SPF records with 3rd party DNS
dns;1and1;spf
To troubleshoot this and get the data I needed, I just sent some test emails to my gmail account and found from the message header that all outbound traffic (for me) is coming from mout.perfora.net and put that in for my spf line shown below.  You will need to verify the last hop server for yourself though.ntxbg.org. 1800 IN TXT v=spf1 include:mout.perfora.net ~allHere is the signature of what to look for in the header to get the name of the last 1and1 mail server before it hands off to the destination:Received: from mout.perfora.net (mout.perfora.net. [74.208.4.197])    by mx.google.com with ESMTPS id e17si10739617wiw.45.2014.11.08.19.38.56If you have your own DNS that can be updated with the SPF record either on another registrar or your own servers, 1and1 will work fine for email. Otherwise prepare to have much of your email marked as spam.