[IMail Forum] Tightening security on mail relay

[don]

We recently found that one of our domains is listed in a database of domains that could POTENTIALLY be used for mail relay.  Some administrators subscribe to these database lists and refuse mail from these domains.  We need to fix this!!   We are running IMail 5.x and relay for local hosts only.  They got around the local host only issue by sending from spammer@our_domains_IP_address!  What can I do to stop relaying when they use our IP address??   Thanks, Don Winsauer