Sorry for the OT post, but I'm stumped and hope someone here can enlighten me.

When sending to a mimecast users, our mailserver timed out with.  Looking at 
the logs, I see:
Aug  9 07:39:48 smtp postfix/smtp[31712]: 060641011CF: host 
us-smtp-1.mimecast.com[205.139.110.139] said: 451 Hostname is not authorized - 
https://community.mimecast.com/docs/DOC-1369#451 [3xVXmRAsN4awNrHIyHCW5Q.us94] 
(in reply to RCPT TO command)

Looking at the web page referred to in the log entry I find this:
451     Hostname is not authorized      Omni Directional hostnames is enabled.  
Disable Omni Directional hostnames.

I did a web search but can't find any other reference to "Omni Directional 
hostnames".  What are they referring to that they don't like about the sending 
hostname (smtp.ci.juneau.ak.us)?  No other domain is rejecting messages based 
on the hostname and the phrase "Omni Directional hostnames" doesn't seem to be 
industry standard nomenclature.  At least not that I can find in my searches.

I sent a query to postmas...@mimecast.com which was duly rejected (not awfully 
surprised):
'postmas...@mimecast.com' (postmas...@mimecast.com)
Your message couldn't be delivered because delivery to this group is restricted 
to authenticated senders. If the problem continues, please contact your email 
admin.

Again, sorry for the OT post but if anyone knows what the heck they're talking 
about I'd appreciate it...

...Kevin
--
Kevin Miller
Network/email Administrator, CBJ MIS Dept.
155 South Seward Street
Juneau, Alaska 99801
Phone: (907) 586-0242, Fax: (907) 586-4588 Registered Linux User No: 307357


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