My Exchange server is running Exchange 2000 on a Windows 2000 server which resides on a DMZ on our firewall. We are able to send and receive e-mail within the company, but when someone tries to send an e-mail outside of our domain, it is immediately rejected with the response that "none of your e-mail accounts could send to this recipient". Likewise, when someone tries to send us e-mail from outside of our domain, the message is returned as undeliverable. I have contacted technical support for the firewall and they have stated that it is an internal DNS configuration problem. I am able to Telnet directly to the Exchange server, so I guess the firewall technical support is right. Any ideas on how I can configure the DNS on the Exchange server so people can send e-mail outside of our domain? Please help!!