German SMTP blocked by MS

JardeRich

Hi,
Was wondering if there'd been any progress resolving the current issue with the German SMPT being blocked by Microsoft?
Also, did Microsoft eventually offer any explanation as to the reason for the block a couple of weeks ago?
Getting a bit nervous this will become a regular occurrence.
Thanks.

nhughes

To second JardeRich's query. We have had repeated problems with the German SMPT being blocked, not just by Microsoft, and would like to know if there is a more permanent way to prevent this from happening?

poke50uk

Yes - ours is being blocked too. Critical time for us as well!
550 5.7.511 Access denied, banned sender[139.162.136.213]

sean

We've received no word from Microsoft regarding the current incident nor the previous incident.

Please rest assured that we'll update the status page at https://status.opalstack.com/incidents/99 when more info is available.

fzin

Same as @JardeRich , @nhughes and @poke50uk Using German related mail services.
These blacklists are becoming very annoying.

Why is the German SMTP server so often blacklisted and the US SMTP server not?
I assume that the same configuration is used.
Same terms of use So that any abuse at both is remedied in a timely manner to prevent possible blacklisting.

I do see that US is based on upstream Leaseweb and the German equivalent on Linode.
Why not also the German SMTP servers on Leaseweb?

I have recently had more mail servers on Linode and blacklists are unfortunately very common. And unfortunately it is not only Microsoft that blacklists for almost nothing. (Also unjustifiably so). Apparently Linode's IP block has a very bad reputation and little needs to happen for another blacklist to appear.

Because nowadays mail from the big 3 (Google. Microsoft and Amazon) functions strongly on the basis of IP reputation and reputation in general.

Hopefully there will be a permanent solution. Thank you for the action and response @sean

sean

fzin we're looking into using an alternate IP address for the DE SMTP, but we've actually moved our German SMTP from Leaseweb to Linode because of poor reputation at Leaseweb several months ago.

The US SMTP has had its own share of block issues in the past for the same reason.

There's never going to be a permanent solution to spam and the related risk of being blocked, at least not without a complete overhaul of how email itself works, but we can all work together to minimize that risk.

For our part, we monitor outgoing mail and quarantine all of the spam that we detect. We have to do that conservatively because of the risk of false positives, so some spam is always going to make it out. That's where you all can help.

For your part:

Website forms are, by far, the largest source of spam that is sent from our mail system. If you have a website form that generates an email message, like a contact form or registration form, then secure that form with a CAPTCHA, honeypot, or any other available measure to make it harder for spam bots to abuse your forms.
If you use a mailing list then ensure that your mailing list is confirmed opt-in only. If it's not, then you can't use that mailing list to send any mail via Opalstack's email service, and you can't use it to send mail from ANY mail service if the messages advertise a site or domain hosted at Opalstack. This is a requirement of our Acceptable Use Policy.
If you're a spammer, kindly go host your junk somewhere else and rethink your life choices. 🙂

sean

@all we've switched the IP address on smtp.de.opalstack.com and I can already see that MS is accepting mail from the new server. We'll continue to watch for problems.

JardeRich

Thank you Sean for your efforts, it's much appreciated.
I too can see that emails are beginning to move again.