SPF-DNS

Question: Does my domain need a DNS SPF record?

Answer: It is not critical to have an SPF record, however, some sites may prefer to have an SPF record when you send email to them, but SPF is not a requirement.

Question: How do I know my domain has an SPF record?

Answer: From the cli, you can do a quick query, like this: (replace domain.com with your actual domain)

host -t txt domain.com

If you have an SPF record, it would look something similar to:

domain.com text "v=spf1 mx ptr mx:mail.domain.com ip4:65.xx.xx.xxx"

Question: Who do I contact on getting an SPF record?

Answer: Most likely your Internet Registrar.

What's Your SPF Records Say, When Getting "does not designate 74.x.x.x as permitted sender Errors"

This is most likely related to the SPF records for your domain and what the header content of the sending email states as it's Mail From. For example, this is from the header of an email that was "received":

Received: from mail.XYZ-FAKE.com (mailhost.XYZ-FAKE.com [74.X.X.244]) by mta01.ABC-FAKE.com with ESMTP id 
Cft0mO3fjlFGQjTA for <support@ABC-FAKE.com>; Tue, 21 Apr 2009 05:14:13 -0700 (PDT)
X-Barracuda-Envelope-From: testuser@XYZ-FAKE.com
Received-SPF: pass (mta01.ABC-FAKE.com: domain of testuser@XYZ-FAKE.com designates 74.X.X.244 as permitted sender) 
receiver=mta01.ABC-FAKE.com; client_ip=74.X.X.244; envelope-from=testuser@XYZ-FAKE.com;

To see what this check was done against, do the following below. I'll trim the output and adjust the information used to protect the innocent. Also, notice how a DNS "alias" might cause an issue here? :

$ host 74.X.X.244
244.X.X.74.in-addr.arpa domain name pointer mailhost.XYZ-FAKE.com.

$ host mailhost.XYZ-FAKE.com
mailhost.XYZ-FAKE.com has address 74.X.X.244

$ host mail.XYZ-FAKE.com
mail.XYZ-FAKE.com is an alias for mailhost.XYZ-FAKE.com.
mailhost.XYZ-FAKE.com has address 74.X.X.244

$ dig XYZ-FAKE.com MX

;; QUESTION SECTION:
;XYZ-FAKE.com.			IN	MX

;; ANSWER SECTION:
XYZ-FAKE.com.		3600	IN	MX	22 serverA.DNS-FAKE.com.
XYZ-FAKE.com.		3600	IN	MX	11 serverB.DNS-FAKE.com.

$ dig XYZ-FAKE.com TXT

;; QUESTION SECTION:
;XYZ-FAKE.com.			IN	TXT

;; ANSWER SECTION:
XYZ-FAKE.com.		3600	IN	TXT	"v=spf1 a:mail.XYZ-FAKE.com ~all"

Useful links:
http://old.openspf.org/wizard.html
http://www.mxtoolbox.com/SuperTool.aspx