i have a forum which emails new members for confirmation codes, but i was testing it out and then i realized that the email is being sent to yahoo bulk mail folders.
i went ahead and looked at all the headers and found. X-YahooFilteredBulk
since i have a block of 8 IP's i went ahead and change my server so that the e-mail client on sendmail sends through a different IP address, and i verified it by sending some email to myself and checking the headers.
sure enough looks like my whole block is blocked and tagged as spam. i just got this server in march of this year and i have never used sendmail on it.
i went ahead and installed it so i could use the phpBB forum software, and this happens.
could anyone direct me to solution? is there a way to tell yahoo that i am a legit non-spammer?
It's not trivial, and it's not entirely clear that it accomplishes your stated goal. Setting up a sendmail milter is not something many people can accomplish on their own. Even if you get it right, not every provider has adopted domainkeys, you'd probably need SPF records too. [openspf.org...]
SPF is a lot easier for an individual webmaster to achieve than domainkeys. All you need to do is get a couple special txt records added to the zone file for your domain. Most hosting providers are getting hip to this and will play nice.