I take it the mailserver is hosted in the cloud and is not an Exchange
server?
Anyway, if I understand the symptoms, I'd guess the email is getting to the
recipient's mailserver and is being rejected by some poorly configured IP
reputation rule that is looking at the sender's IP in the headers instead of
focusing on the mailserver's IP and trusting it to authenticate the sender.
(I'm assuming, perhaps incorrectly, that the IP is different depending on
which building the computer is in.)
Does this happen to all recipients or just certain recipients?
-----Original Message-----
From: Bill Prince via Af
Sent: Thursday, October 30, 2014 7:58 PM
To: Motorola III
Subject: [AFMUG] outlook becomes "intermittent" in satellite office
This is a bizarre set of symptoms, and I really don't know what is going
on. So I will articulate the facts, and maybe one of you can tell me
what might be wrong.
We have a business subscriber that occupies several buildings. The
buildings are separated by enough distance that we have to interconnect
by means other than vanilla ethernet.
Our service is delivered to their main office. Our SM is installed
there (PMP450), plus a Mikrotik router on ROS 5.26. The Mikrotik
manages 4 VLANs; 1 business VLAN, which is bridged to the main subnet in
the main office. The other 3 VLANs are guest VLANs; each on their own
(private) subnet.
All the computers, etc. work fine in the main office.
The main office is connected to the "guest building" with a VDSL modem
(~~ 800' phone line between buildings). Not much occurs in the guest
building; it has a couple of WiFi APs for the guests.
In the guest building, we've installed an RB260GS switch. It divides
the various ports out to 4 different VLANs. A couple ports are the
"business VLAN", plus 3 different "guest VLANs". The SFP port on the
RB260GS is used to connect to the "satellite office" another couple
hundred yards beyond the guest building. The SFP port is on the
business VLAN.
At the satellite office, they have 2 computers. Everything on the 2
computers in the satellite office seems to work just fine. Web
browsing, streaming youtube, etc.
However, when they run Outlook, "some" email doesn't go to the
destination. As far as we can tell, it gets to their off-site SMTP
server (Globat), but some of it doesn't ever reach its destination. If
they use their web-based email, the email works every time. Also, the
POP part of the email works just like you'd expect.
Today, we moved one of the computers back to the main office, and
surprise, surprise, Outlook starts working just like it's supposed to.
We've run extended ping tests between the satellite office and the main
office, and there is no break in the link. It seems solid. So
where/how is the SMTP part of email breaking?
What tests can I run to figure this out?
--
bp
