I am setting up new system and this issue may not be a real problem (yet, guess).

When try to send mail locally from-to same dm/po to user which is not known to GW e.g. fakeuser@mycompany.com, the mail was sent out to internet to outside server.
In fact at the moment GW is in testing phase while other system is still in production. So, mycompany.com exist outside, there is DNS record about too.
For known users within GW mails delivers locally, without touching anything outside GW system.
What I expect to hapen is that local GW don not even try to deliver outside when user is unknown within internet domain.
What I missed?

GW is installed at single server (SLES) , single domain, single PO. Just few users are set from eDir for testing purpouse.