Thanks Jim But can't Exchanger server, on receiving a mail destined for another domain, re-send the mail (or in other words forward the mail and act simply like a relay agent). Otherwise is there any way that I can achieve my goal of allowing only Exchange server to send mails out of ISA (and redirecting mails from other SMTP servers to the exchange server for further transport). Thanks Nitin -----Original Message----- From: Jim Harrison [mailto:jim@xxxxxxxxxxxx] Sent: Wednesday, August 28, 2002 6:57 PM To: [ISAserver.org Discussion List] Subject: [isalist] Re: Custom application filter development ... http://www.ISAserver.org That's a pretty complex design, since it also requires the main Exchange server to accept mail destined for domains it doesn't hold. Jim Harrison MCP(NT4, W2K), A+, Network+, PCG http://isaserver.org/pages/author_index.asp?aut=3 http://jalojash.org/isatools Read the books! ----- Original Message ----- From: Nitin (Indigo) <mailto:nagarwal@xxxxxxxxxxxxxxxxxxxx> To: [ISAserver.org <mailto:isalist@xxxxxxxxxxxxx> Discussion List] Sent: Tuesday, August 27, 2002 10:18 PM Subject: [isalist] Custom application filter development ... http://www.ISAserver.org Hi I am trying to make a SMTP filter that would redirect all SMTP traffic coming from the intranet (except from the Exchanger server) to the Exchange server. Reason being I want to restrict only Exchange server to be able to send mails (for tracking purposes). I also don't want to configure other SMTP servers individually to relay to exchange server. Just wanted to know if someone has made such/similar application filter using ISA SDK. Thanks Nitin ------------------------------------------------------ You are currently subscribed to this ISAserver.org Discussion List as: jim@xxxxxxxxxxxx To unsubscribe send a blank email to $subst('Email.Unsub') ------------------------------------------------------ You are currently subscribed to this ISAserver.org Discussion List as: nagarwal@xxxxxxxxxxxxxxxxxxxx To unsubscribe send a blank email to $subst('Email.Unsub')