Monthly Archives: March 2017

Permanently reject a specific email sender address using postfix

Postfix generally accepts all sender addresses. It might be needed in some rare cases to reject one sender addresses for some┬áreason. With postfix, there is the possibility to use the “check_sender_access” to set individual actions per sender address. For the … Continue reading

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Certificate Transparency and unauthorized certificates

I own a domain which was bought a few months back which is managed by CloudFlare’s service in DNS-only mode. As I intended to only use CloudFlare’s DNS service, I disabled every option except the DNS related features. You can imagin the surprise to see certificates issued for my domain without my knowledge. Continue reading

Posted in Security, Web technologies | Tagged , , , , , | 1 Comment