We are running Exchange 2003 on Windows Server 2003
For whatever reason we have intermittant issues sending e-mail to these organizations. The messages time out as non-deliverable. The addresses are known good addresses. I've check dns resolution through nslookup and can get to the mx records with no problem. I can also telnet to the mx addresses on port 25 so I know the server addresses are good.
I've also ran our domain against serveral blacklist databases and we come up clean. I've also verified that relaying is turned off.
I have heard over the last few months that these organizations were going to implement an antispam system called SPF.
Question: Are the service providers listed above using SPF or is there another issue at play?
Thanks in advance for the assist.