Thanks Tiago I was implimenting VPN in Site 2.When i give a valid IP on the Server it becomes an open relay.To prevent that i added the Ip`s of servers in Site 3 & Site 4 in Routing restrictions.But the problem is they get unable to relay error. Thanks Harry -----Original Message----- From: Tiago de Aviz [mailto:Tiago@xxxxxxxxxxxxxxx] Sent: Wednesday, January 28, 2004 10:59 PM To: [ExchangeList] Subject: RES: [exchangelist] Relaying Problem http://www.MSExchange.org/ This is a multi-part message in MIME format.