Entries by Stefan Cink


Recommended security update for CVE-2018-8421

With the last Microsoft patchday on September 12th, a security update for the .NET framework was released, which closes a critical vulnerability. To exploit the vulnerability, the victim must open a document specially prepared by the attacker. Even if there is no direct danger for NoSpamProxy customers, we recommend installing the update. Further information and […]

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Outgoing e-mails are rejected with “Unable to relay”

Dear NoSpamProxy customers, since a few hours we see in customer environments that send outgoing e-mails from O365 via NoSpamProxy the error “Unable to relay”. We found that Microsoft uses a new certificate to identify all Office 365 email servers, which was issued by a GlobalSign CA rather than Microsoft’s own CA. The NoSpamProxy security […]

Analysis of the Cyren outage of 20 March

On March 20, there was a short interruption in the processing of e-mails, because the query of the mail hash values by the Cyren service did not work. We apologize for any inconvenience caused by NoSpamProxy. Our partner Cyren, who operates a worldwide network for checking e-mails, has now provided us with a root cause […]

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How to use SPF-authenticated servers in “Corporate email servers”

Similar to Microsoft Exchange, some NoSpamProxy features can only be enabled through a PowerShell cmdlet. Specifying an “SPF-authenticated corporate email server” is one such feature. Entries of this kind facilitate the maintenance of NoSpamProxy enormously. “Corporate email servers” define the servers of a company that are allowed to use owned domains in email sender addresses. […]