drs. ing. Willem L. Middelkoop
IT ondernemer, investeerder, hacker en software ontwikkelaar
Visiting an international hackers conference
OWASP Global AppSec Amsterdam
This month I was lucky enough to attend Global AppSec Amsterdam, an international conference for hackers and security specialists. There were presentations from former intelligence agents, bounty hunters, academics and software vendors. I learned about some of the newest hacking techniques, met with interesting people and played some cool retro games. Read along for more.
Fighting backscatter spam at server level
Configure Postfix to block spam before it enters the server
This month I had to deal with backscatter spam, affecting one of the mail servers I manage. As server engineer I make sure that servers don't send spam and that incoming email gets filtered. Despite all good efforts, this server kept being blacklisted for sending spam to iCloud, Office 365 and Google Gmail for Business (G Suite). Read along to find out how what caused this and how to fix this.