Hello I got two Exchange 2007 servers in different forests. Each Exchange 2007 server hosts mailboxes for users with different SMTP domains. For example ExchangeA serves mailboxes for @a.com , @b.com and @c.com domains Exchange serverB serves mailboxes for @d.com , @e.com.au, @z.org The corporate would like to allow cross forest free/busy lookup between the exchange servers no matter what is the remote user SMTP address. For the sake of the question it doesn't matter if the f/b data is basic F/B or granular. The issue here is how to handle the fact that each exchange has a multiple SMTP domains. Based on what I read the remote forest availability service will look for the autodiscover for the remote requested domain in order to get the information (But will not be able to use SRV redirection DNS record). This means that each Exchange needs to have an autodiscover virtual directory for each SMTP domain hosted. The two exchange servers can use internal DNS records not reflected to the external world, or even local resolutions via HOSTS file. What is the best solution to go about it ? 1. Can I create a new web site and implement an additional autodiscover virtual directory on it and use a wildcard certificate to allow all the SMTP domains to be forwarded to it ? 2. Should I create additinal web site and autodiscover virtual directory for each SMTP address space ? 3. None of the above ? a different idea ? Thanks