I'm trying to use sendmail to mail from a machine that isn't in an Active Directory domain, to a user account that IS in the Active Directory domain. It appears to be connecting to the Exchange server, but it doesn't do anything. Here is an example:

[root@qamail ~]# mail -s Testing qa@w2k3ee4.labad2.mylab.lab
BlahBlahBlah.
Cc:
[root@qamail ~]#

w2k3ee4 is the Exchange server.
qa is the user.
labad2 is the AD domain.
mylab.lab is the FQDN (the tail of the FQDN is not the issue)

No error reported, but it seems to be being ignored by the Exchange server.

Oh, and here's the maillog, only line reported at time of sending:

Apr 7 13:48:03 qamail sendmail[28064]: n37Gm36o028064: from=root, size=83, class=0, nrcpts=1, msgid=<200904071648.n37Gm36o028064@qamail.mylab.lab>, relay=root@localhost