Last month we decided to move from our older server to a newer, more powerful box. Moving the majority of services didn’t worry me, but knowing how fragile and potentially awkward the mail can be did give me pause. I spent some time and researched the settings and configuration, tested it as best I could and then made the move. All seemed fine for 75% of the users, but a small issue was troubling the rest, so I adjusted the configuration and watched the results.

As usual things were a mix of good and bad, but some spam did get sent. I quickly fixed the problem and moved on. Now 90% of the users were fine but the remaining 10% comprised the most vocal and so suddenly it felt as if 90% of the users were having troubles.

I tweaked a setting here and there over the next few days, but nothing seemed to work. The complaints grew and the language performed the usual subtle changes of tone that desperation seems to trigger. With hindsight the fact that the affected now numbered less than 5% should have signalled me to pause and take more time. Needless to say I adjusted another setting which opened the floodgates! Initially it didn’t seem like an issue as mail was being delivered and spam was being rejected.

Having removed a level of protection too far eventually a spammer found the issue and exploited it. As always this coincided with me being away from keyboard for 8 hours, so the server was subjected to a massive deluge of spam. As soon as I was back I stopped things and removed as many messages as I could before they were sent. Restoring the old configuration I reviewed my changes and found the problem, adjusting the configuration and eventually restarting deliveries. This time I watched and saw that the spam flood had been stopped. Even better the noisy 5% were now happy. Getting into bed at 3am felt good that night.

Of course that was just the start. Having been open for a short period several blacklists noticed and added the IP to their lists. Many hosts refused to talk to the server, so I started contacting the blacklist providers and attempting to restore the reputation of the server. Over the next few days most accepted the explanations and seeing no more spam originating they removed the IP. Things returned to normality – except for Outlook.

I thought that dealing with AOL was going to be the most problematic given their odd and highly aggressive anti-spam configurations, but actually following the steps on their website had the situation resolved in a matter of days. Outlook on the other hand was a whole different ball game.

The first problem is where do you go for help in getting the problem cured for Outlook domains and addresses? The error message in the logs looks like this…

Jan 6 13:43:04 xxx: xxx: to=, relay=xxx, delay=7.5, delays=2.2/0/0.28/5.1, dsn=5.7.1, status=bounced (host[xxx] said: 550 5.7.1 Service unavailable; Client host [xxx] blocked using Blocklist 1; To request removal from this list please forward this message to (in reply to RCPT TO command))

That’s fine, but of course I didn’t send the message. The person who did send the message wasn’t interested in forwarding it and simply deleted the returned message having noted that it wasn’t delivered. Not an unusual response from an email user I would suggest. As the person who tried to administer the server surely there is a webpage or some such that can be used to accomplish the same thing? Every other blacklist provider has one!

After searching around I find which offers lots of interesting advice and links. Following them I jump through the hoops and sign up for the various programs they highlight. Then I send them a message via with the information that they ask for.


No explanation or further help is offered. When I reply the message is – yes you guessed it – bounced as the server is blacklisted! Oh, you couldn’t make it up. Trying again with a different email on a different service gives the same denied result and all attempts to find out why are met with a blank wall of copy and pasted text that gives no additional information.

I can sympathise that is a huge target for spammers, but making it so hard for others to interact with the service simply means that people will increasingly not interact with it. Large corporations may be able to employ people to spend the time required to deal with the issues, but smaller companies can’t afford such luxuries.

As I typed this I forwarded on a bounced mail to the email address and received 2 responses – one saying the message was being processed and another saying the message couldn’t be processed as they didn’t understand it! How can such a large organisation as Microsoft make things so difficult?