Exchange 2K7 - restrict send to a few domains?

[PiqueABoo]

There's a bunch of younger users with mailboxes in their own storage group/store.

 

I want to be able to stop them sending external mails anywhere besides some permitted domains, in fact ideally that would include permitted wildcards e.g. *.sch.uk. And vice versa for receiving.

 

I'm struggling to find a way that doesn't involve writing a little "transport agent" and I'm not convinced that will be ideal e.g. can you figure out that an outbound mail is from someone with a mailbox in a particular store, and vice versa for inbound?

 

Anyone got any clues on how to do this with minimum effort?

[Geoff]

Wouldn't Sender Filtering do what you want?

 

Sender Filtering

[PiqueABoo]

Thanks for suggesting, but no. I 've done a *lot* of googling since and eventually turned up two comments from different MS folk saying that you need to make a custom agent just for the outbound half of what I want.

 

So I've made a custom agent and it's working so far(!) on the lab bench, but is still being tested. Should anyone else be faced with this problem:

 

a) If you've got a single Exchange 2K7 doing everything you must make a custom "routing agent". Most of the few examples you can find are for an "SMTP receive agent" but for a single Exchange 2K7, they won't catch outbound messages.

 

b) I haven't found a quick way to decide that a message is from a user with a mailbox in a given store (or addressed to a user with...). Given that they're interfering with every message I reckon agents need to be quick, but fortunately there is a strict naming convention for accounts and mail addresses, so I'm able to use simple checks based on mail addresses instead.

 

c) Took some thought, but it wasn't too bad to write @ 200 lines of code (includes getting all the config from the registry). It's been a bit tedious to test it though.