outgoing spam marking??

[zagman76]

Hi - we have extended our lab testing to include a few external clients to the zimbra system. We have a remote office that has users with zimbra accounts, and a lot of the e-mail they send to us (abc@domain.com -> def@domain1.com, and both are hosted on the Zimbra box) is being marked as spam??!? Shouldn't the system know that both domains are internal, and not treat that e-mail as spam?? Does zimbra have to be explicitly told what domains are internal, and therefore *not* check for spam?

Thanks!