Mail routing issue / domain merge

Hi everyone

We have a rather complicated (for us) mail routing issue. My company (comp S) where bought by another company (comp G). We are both running domino/notes. We are currently cross-certified with each other and we are routing mail and replicating databases between our servers but we are still on 2 different domains.

We where just told by management that certain people at my company (comp S) are going to change mail addresses to the same address as the company that bought us (comp G) are using. So I will get my mail address changed from name@compS.com to name@compG.com. My account will be kept on server S. Users in company G will keep their addresses @compG.com and there will still be users in company S that will have @compS.com as their address.

Ofcourse incoming mail to my new mail address will be delivered to server G because this is where the MX records points them. First question is - how can we make this mail travel over to server S for delivery to my mail file? Server G have a replica of our address book and this is added to DA, but it seems the server is not looking up addresses in this address book for external mail delivered to server G. Is there any way to change this? We’re getting a “smtp; 5.1.0 - Unknown address error 550-'xxx.xxx@compG.com… No such user” when testing even if compG.com have been added to my username/shortname field and server are supposed to look into these fields (fullname then local part enabled). We are looking into the “local internet domain smart host” setting to get these messages over to server G but not sure it’s the way to go.

Next question is ofcourse outgoing mail - to prevent any issues with blacklistings/spf etc. we are planning on routing all outgoing mail through server G by setting this as relay host for server S (to prevent both server G and server S claim they are @compG.com). This will in turn send ALL mail from @compS.com through the G servers, which again forces us to let the G server handle also incoming mail to @compS.com messages. These needs to get delivered to server S.

We are considering merging our domains so that all servers/users in domain S becomes domain G, so that we get one shared address book - will this simplify things? Are we required to merge to be able to do what we want?

Complicated issue to describe here in a few lines - but really need some thought around the issue.

Hope someone can help

Stein