The RUS, or lack thereof, is not involved with mail delivery. http://www.msexchange.org/tutorials/MF017.html -----Original Message----- From: Ara Avvali [mailto:ara@xxxxxxxxxxxxx] Sent: Sunday, October 02, 2005 2:54 PM To: [ExchangeList] Subject: [exchangelist] RE: exchange as a domain controller and fail over I mean incoming outgoing emails -----Original Message----- From: Andy David [mailto:adavid@xxxxxxxxxxxxx] Sent: Sunday, October 02, 2005 11:46 AM To: [ExchangeList] Subject: [exchangelist] RE: exchange as a domain controller and fail over The RUS wont run if it points to an invalid server. Not sure what you mean by all communication. -----Original Message----- From: Ara Avvali [mailto:ara@xxxxxxxxxxxxx] Sent: Sunday, October 02, 2005 2:41 PM To: [ExchangeList] Subject: [exchangelist] RE: exchange as a domain controller and fail over Andy, Thanks for reply. My concern is if such a thing happens and RUS is not updated manually, does that mean all communication is lost till then? Thanks ________________________________________ From: Andy David [mailto:adavid@xxxxxxxxxxxxx] Sent: Sunday, October 02, 2005 11:25 AM To: [ExchangeList] Subject: [exchangelist] RE: exchange as a domain controller and fail over If the Exch Server is on a DC, then Exch services such as DsAccess, DSPproxy and such will not fail over and will only point to itself. RUS will have to be manually changed to valid DC. ________________________________________ From: Ara Avvali [mailto:ara@xxxxxxxxxxxxx] Sent: Sunday, October 02, 2005 1:31 PM To: [ExchangeList] Subject: [exchangelist] exchange as a domain controller and fail over http://www.MSExchange.org/ Good morning everyone, Would someone clarify this for me? There are 2 domain controllers both 2003 sp1 and exchange 2003 sp1 is installed on secondary. Both as global catalog servers. Exchange is pointing to primary for RUS. If first one fails, does exchange automatically switch to second one which is running exchange? What is the time period for it? Appreciated