Cismic Lemme see if I follow: Ext ISA > Int ISA(SMTP Relay) > ExchangeServer(SMTP) > WebServer(SMTP) > Int ISA(SMTP Relay) or ExchangeServer(SMTP) Ext ISA NIC >> Int ISA NIC(SMTP Relay) > Internal ExchangeServer (SMTP) & Internal WebServer(SMTP) SmartHost = ISA Server The IP on the external interface of the ISA server that's assigned to mail.mydomain.com should publish to the internal exchange server via the SMTP Relay Server. The internal web server uses the internal interface of the ISA or exchange server as its SmartHost to publish to the ISA/SMTP Relay server. SMTPcred.exe points to the internal ISA server but I'm unable to connect to the ISA server from the ISA console on the web server due to permissions and authentication issues. What the preferred or suggested method for testing connectivity in ISA? Thanks