> Each copy of Mercury sends its own mail directly with MercuryE.
>
> This all works perfectly well and is easy to maintain.

Personally I would use MercuryC at the branch offices to deliver all mail to the main site.  Otherwise the main site becomes the gateway host sending/receiving all mail from the domain, including the branch offices.  I do not know if this will fix the problem but since one site gets all the mail and local mail never leaves the local company LANs then it may help.  

I do not normally setup branch offices like this, I normally have all users mail delivered to local mailboxes and use Domain mailboxes to collect all the mail from the users at the branch sites.  I then use MecuryD to pull the mail for the branch offices.   

One real advantage to this is that the branch offices do not have their domain registered in the DNA since they are not getting anything directly from the internet.  You have one IP address and host name seen by the outside word.

YMMV ;-)

We use Mercury/32 4.73 at our main office and two branch offices.

All outside mail to our domain comes to Mercury at our main office - @ourdomain.com,

and we have aliases set up to redirect mail to staff at the branch offices - @branch1.ourdomain.com and @branch2.ourdomain.com.

For example branchuser1@ourdomain.com = branchuser1@branch1.ourdomain.com

At the branches we also have aliases set up - branchuser1@ourdomain.com = branchuser1, just to make sure any local mail is delivered locally and not via head office.

Local domains are defined as ourdomain.com at head office and branch1.ourdomain.com at branch 1 etc.

Each copy of Mercury sends its own mail directly with MercuryE.

This all works perfectly well and is easy to maintain.

The only strange thing is that if someone at a branch (say branchuser1) sends a message with "Confirm delivery" checked to an address at head office, the mail is delivered, then MercuryE tries to send the confirmation to ourdomain.com, not back to branch1.ourdomain, ignoring the alias that is set up for branchuser1. MercuryS on the same machine refuses the connection from itself because the transaction filtering is set up to refuse connections from anyone pretending to be ourdomain.com.

This is not a major problem because we can live very happily without delivery confirmations, but it seems to be wrong.