I am an I.T. Administrator and have some questions about your product and blocking. We have a client who uses Zimbra for their e-mail service. When we try to e-mail them, it comes back as rejected. If I try to telnet into their server, it refuses our connection to them right away. I think they are blocking our IP range because if I go to another network, the HELO does respond. Any ideas?

I never heard of Zimbra, are you a hosted solusion or a software package?