Split domain email via two different SMTP servers

In theory you can "sort" email with a SMTP Proxy server.

Might be easier just to use two domains.

joe.staff@bc-online.com

sales@BigCompany.com

You keep your outside face aligned with your branding, and use a internal/intranet domain for all the staff traffic.

Postfix will do it with a virtual alias and a transport map sending selected addresses to a second server.

virtualaliasmap:

sales@domain.com  sales@server2.domain.com
support@domain.com support@server2.domain.com

transport_map:

server2.domain.com smtp:server2

Alternatively you could use simple aliasing which would work in postfix and sendmail to send the mail to server2:

/etc/aliases:

sales@domain.com  sales@server2.domain.com
support@domain.com support@server2.domain.com

Either way you can't tell the world to send mail to different servers based on username alone. The mail has to go to one server where some of it is filtered and resent.

If at all possible don't do this. Do as vonskippy's suggests and use two domains. It makes the configuration so much simpler and complexity causes failures. One domain could be a subdomain of the other. E.g. sales@mycompany.com, my.name@people.mycompany.com.

Thanks for the information. I wish I had thought about this a bit more before I initially set up my email infrastructure. Using a sub-domain for staff email addresses would have made perfect sense.

I'll have to have a bit of a think regarding this since I already have personal email addresses configured and in use.