[SOLVED] configure Sendmail to co-exist with another mail system

[tomjerry]

Hi,

I am very new to Linux world, i need some help with sendmail.

We are in the process of migrating our email system from sendmail to another email platform. Due to the number of users in our organization we opt to migrate the users in groups and during the interim period, two different email system will run in parallel.

My question is how to configure sendmail in such a way that for any user who has been migrated to the new email platform, it will forward the email destined to that user to the new email server, and any email destined to local user remain sent locally. Currently we were unable to get the configuration right -- either sendmail forward all email to the new mail system regardless of whether the user is local or otherwise, or it sends NDR bounce to any user account that is already migrated to the new mail server.

Both email system host the same domain name, and the idea is that this should be transparent to the user -- no configurations of user's email settings is required, until we migrate them to the new mail system.

Any help would be much appreciated!

Regards,
tomjerry

[Roxoff]

I think you'd do this through mail aliases. Leave your sendmail machine as your main mail host for now, but for the users who've been migrated, set their mail alias in the sendmail configuraton to forward all mail to <username>@newserver.<yourdomain>

[tomjerry]

Hi Roxoff,

Your post really helps. we are able to configure the way we want it to be, now two mail system can co-exists. It gives us a the flexibility we need for our migration strategy. Thank you so much.

Best Regards,
tomjerry