SBS 2011 - Using Exchange / Static IP - Cannot send e-mails to certain domains

Question

Hi,
Client is running SBS 2011 using Exchange to send and receive e-mails.  For some reason 5 days ago they got call from clients stating they had not received e-mails from them (stpeterdeland.org). I ran the online Exchange Analyzer - (No errors). The
strange thing is the client was not receiving "NDRs". i talked with one IT admin for one of the domains. He saw our e-mails being held up by his spam filter and has since "White Listed" the domain IP (65.34.20.210).
I also ran Exchange BPA - No problems noted. Any help on this would be greatly appreciated.
Thank you,
Frank
Frank

Answer 1

You have your answer: spam filtering. The clue was 'no NDR', when emails disappear without trace, it is almost always because something has designated them 'spam'.
You can't really do much about this unless you know why the emails are being flagged. Possibly your contact can help here, most anti-spam systems do explain why they mark down particular emails. Spam filters use many criteria, some of them even rational.
I once found that a client's emails were disappearing because of a picture used as a signature: it was a .jpg file, and the problem was solved by substituting a .png file. That's one hint: do not include files which can carry malware, or at least not unless
zipped, preferably with a password. Unfortunately, there are not many file types which cannot include malware. Outlook drops broad hints if you try to attach certain files, and suggests you might wish to reconsider.
Another minus is the use of HTML email, which is unfortunately almost universal now. Plain text emails are less likely to get the thumbs-down, but I'm not sure if the MS webmail can even originate plain text emails. Obviously, there are certain words to
be avoided, and I won't mention any here, but many apparently innocent financial and entrepreneurial words will bump up the spam score. Multiple exclamation marks, lots of upper case, the list is endless. I was once trying to help a client's salesman set up
a VPN connection, and had my email killed by Yahoo because it contained a URL and some other networking information.
The only really certain way to find out why emails have been dropped is to ask the admin of the recipient, or of any smarthost used on the way. You do have to hope that they actually have an admin to ask...
Joe