Topic: large number of pseudonyms - any known issues?

[grimblefritz]

I've been asked by an organization to setup a server to perform email forwarding. The requirements are very simple. Taking a couple of arbitrary user names and destination accounts:

user1@organization.com forwards to bill@yahoo.com
user2@organization.com forwards to bob@gmail.com

There will be several hundred of these forwards.

There will perhaps a hundred accounts (not forwarded) that receive mail to a local user account, to be accessed either via web mail, pop or imap.

I know SME Server provides the functionality:

http://wiki.contribs.org/SME_Server:Documentation:Administration_Manual:Chapter9#Pseudonyms

As I had experience with SME Server years ago, it seems a perfect solution to place outside the firewall in server and gateway mode, but with no connection on the internal LAN port. There are a couple of other capabilities they're looking for that are easily addressed this way. It is only the email portion that I'm concerned with.

With regard to email, the one thing SME Server gives me is a very simple way to maintain the email forwarding list, and to reliably build the resulting configurations. It will take little to create the interface to manage everything.

I have some questions regarding performance.

On a reasonably modern but low end server, is there adequate processing power to handle 1000+ mail accounts, with 90% or more being pseudonyms with no matching user account? I realize the time to expand templates might become substantial, but changes will be infrequent (3-4 times per day at worst) so that delay is not a problem. I'm more concerned if there are operational delays in performing the forwards themselves. The assumption is an average of ~100 messages per day per account.

What happens when a message is bounced by the forward target? That is, mail to bob@gmail.com could be refused by the gmail servers. Does the bounce route back through the SME Server, or are things (or can they be) configured so such bounces bypass SME Server?

What happens if the target account is closed? That is, the bill@yahoo.com account may be deleted or may expire or may otherwise cease to exist. I assume this is a bounce back to the sender. What I'm really interested in is this: Is there a way to intercept/detect such a condition and create an exception report for the organization?

Lastly, what have I not thought of? Are there major pitfalls to using SME Server in this mode?


Thanks!