|Something odd is going on.  We have over 1300 pieces of mail queued for
|mcimail.com, some of it for as long as 5 days.  NSLOOKUP says the two
|mail engines (and correct me if I'm confusing something) are gatekeeper4
|and gatekeeper3, right?  I tried teleneting to port 25 on both of them
|and they look plausible to me.

Check the IP addresses in the SMTP q for that host and then compare those
with the IP addresses returned by the authoritative DNSes.  Do they
match? If not, those mail messages will probably time-out after your SMTP
retry interval.  At least that's what happens on VM/CMS SMTP clients.

/Pete