Dear expertise, Our company has assigned me a task to integrate our sub-company?s mail system with main company. In present we are running at my place (main company - company A ? companya.com) ? exchange 2000 SP4 mail server. I have to setup another exchange server at sub-company (Company B ? companyb.com). These 2 companies are physically in 2 locations (nearby). 2 companies are connected by fiber optical cable and it will inter-connect to our internal switches ? different subnets, company A ? 10.1.1.x & company B ? 192.168.128.x. Our requirements are: Company A must have to access Company B?s Global address List. Company B must have access to Company A?s Global Address list Company A user must capable of logon to Company A Domain in Company B?s network Company B user must capable of logon to Company B Domain in Company A?s network My deployment is: Placing the Domain Controllers - Place companyb.com domain tree in companya.com forest Create a new administrative group & routing group before Install E2K server in company B E2K server Company A Domain Controller is the Catalog Server & 1st domain controller in the forest. My question is: can I achieve my objectives in this type of deployment. Please give me your suggestions/comments to guide to the correct direction to accomplish on my task Thanks in advance, - Hirantha