Hi Ravi, You can only have a single external interface of the ISA Server. So, you won't be able to publish your mail server on the interface that doesn't have the default gateway set. HTH, Tom Thomas W Shinder www.isaserver.org/shinder ISA Server and Beyond: http://tinyurl.com/1jq1 Configuring ISA Server: http://tinyurl.com/1llp -----Original Message----- From: Ravi Kumar [mailto:kakinadaravi@xxxxxxxxxxx] Sent: Monday, March 31, 2003 4:26 AM To: [ISAserver.org Discussion List] Subject: [isalist] Port mapping http://www.ISAserver.org Hi Our company got a leased line and dialup line for backup. We access mail server thru this. We want to configure the network so that clients can access our mail server thru dialup also when LL is down. But for this all clients required to have specific IPs which is not possible. Can I do the NATting in ISA server. Anybody pls help me with the procedure. Free Trial Software: Monitor & Manage Web Use with SurfControl Web Filter for MS ISA Server http://www.surfcontrol.com/go/zisadl1