Hi forum, Since a few days we have problems sending mails out where the sender is not related to the exchange server. Our Exchange works for 3 companies as smtp server. Until now there wasn't a problem, but due to the new anti-spam rules, there is no reverse DNS lookup possible for the domains that have another mailserver set to receive mails. They have a hosting outside the company to receive the mails, but use our exchange to send out. Are there some settings I've to do to make sure the mails go out without problem? I'm not an exchange specialist but have to solve this problem.

Check with the hosting company and find out if the will relay mail for you. If so set up the appropriate send connector(s) on your exchange server to send you outgoing mail to that relay server. Bill

Sending email through your Exchange server for another domain shouldn't be a problem. There aren't enough IP addresses in the world for every domain to have its own IP address to send email from. You need to check with the hosting company what measures they have put in place. If they have deployed SPF records or similar then you will need to have your server/IP address added to the SPF record so that you can continue to send email. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.