I have been searching around, but not sure of all the facts I need. Let me explain.
I have stayed out of the SMTP game for a while and have become ignorant of the newer developments.
Prior to my current IP address, it was a commercial IP address from a Sprint pool out of Florida. It was never challenged when I sent e-mails. But since CenturyLink has taken over Embarq after the merge with Sprint (land line), my DSLAM was changed and the IP address updated to a subscriber line (which I am paying for I assure you - another fight for another day). Since then, I have only sent two e-mails and both to Yahoo! addresses - one just a while ago. The first one failed because I was using my internal DNS for some funky stuff and it needed resetting. I am now using CenturyLinks DNS. However, I never set up SPF and DKIM and though I should.
Okay. That is a lie. I just set up a SPF record - after sending the e-mail. Smart huh? However, while poking around my server, DKIM is not installed and therefore not available at this point. And I am thinking, "Sheesh! Do I really have to do this?"
And that is my question to you. Since my server worked fine before, I am sure I need more today. Is the SPF record enough for Yahoo!, GMail, and others?? Do I really need DKIM? I ask this keeping in mind that there are blacklists that list my IP address block as a subscriber block. This is what would stop my e-mail from going through with some larger ISPs normally and why I never worked too hard. This is an important fact. I need to negate enough negative scores that the subscriber check may not matter if at all possible. Not sure it is.
I would not care except that two of my friends are on Yahoo! and I just responded to one today. As well, being a Landlord that is advertising on apartments guide, rentals, and other online sites, I noticed that all users so far are using Yahoo! and GMail. Nor do I blame them!! So I guess I should care a little.
As it turns out, my e-mail was accepted by Yahoo!, however, I cannot say whether it went into a spam bucket or not. I do not have a notice from Yahoo! saying if my e-mail is rejected as spam or otherwise. I am still concerned with Yahoo! and other e-mail services such as GMail. I almost never send e-mail, but when I do it is often very important.