Hi, It is possible to syncron the addressbook between two companys. The Company don`t have Domain Trust and different Domains. Both company have 2003 Windows Domain and Exchange 2003 A Trust is not possible! Regards Klaus

Hi, I don't think its possible with exchange 2003 without trust, for 2010 we can user frderation trust but you will need 2010 in both ends http://technet.microsoft.com/en-us/library/dd335047.aspx http://technet.microsoft.com/en-us/library/dd335198.aspx And if it exchange 2003 have a look into this post : http://social.technet.microsoft.com/Forums/en/exchangesvrdeploy/thread/d7203f3e-5c53-4510-9dde-0ca2aa2ef499 & if it exchange 2007 have a look into this post : http://social.technet.microsoft.com/Forums/en/exchangesvrclients/thread/ab3bc8ce-e169-44f9-b7b0-67180be6ea3b Do let us know if this didn't help. Ripu Daman Mina | MCSE 2003 & MCSA Messaging

On Wed, 20 Oct 2010 14:29:06 +0000, KSchulz wrote: >Hi, It is possible to syncron the addressbook between two companys. The Company don`t have Domain Trust and different Domains. > >Both company have 2003 Windows Domain and Exchange 2003 > >A Trust is not possible! That would depend on the product you use to synchronize the contents of the two directories. You only need a user-id and password to authenticated in the directories. There's no need of a Forest or Domain trust If that were necessary then synchronization between two different directory architectures wouldn't be possible. --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP