Because a salesperson I know could not send mail to my domain (rare-it.com), I checked the mailserver log to find out what was happening. Turned out that his domain did\/does not have a proper reverse DNS-lookup. That is, the IP address of his mailserver resolves to another hostname than he sends his email from. This is true for my domain too, but I have my office at home, and have a normal connection with a regular ISP. His domain is from a company that exists for about 10 years now.
\nSo, I decided to turn of the reverse DNS check for a moment. I know I switched it on to prevent spam, since most spam is easily filtered because of the failed reverse lookup.
\nToday I had 24 e-mails MORE spam than the regular 1 or 2. That’s 1 day. You know what will happen when I leave this backdoor open. Backdoor is closed again. Nailed shut. Big iron bar. And just to be sure, a bouncer as well. You never know.<\/p>\n","protected":false},"excerpt":{"rendered":"
Because a salesperson I know could not send mail to my domain (rare-it.com), I checked the mailserver log to find out what was happening. Turned out that his domain did\/does not have a proper reverse DNS-lookup. That is, the IP address of his mailserver resolves to another hostname than he sends his email from. This […]<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-632","post","type-post","status-publish","format-standard","hentry","category-uncategorized","category-1-id","post-seq-1","post-parity-odd","meta-position-corners","fix"],"_links":{"self":[{"href":"https:\/\/www.switchbl8.nl\/blog\/wp-json\/wp\/v2\/posts\/632","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.switchbl8.nl\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.switchbl8.nl\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.switchbl8.nl\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.switchbl8.nl\/blog\/wp-json\/wp\/v2\/comments?post=632"}],"version-history":[{"count":0,"href":"https:\/\/www.switchbl8.nl\/blog\/wp-json\/wp\/v2\/posts\/632\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.switchbl8.nl\/blog\/wp-json\/wp\/v2\/media?parent=632"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.switchbl8.nl\/blog\/wp-json\/wp\/v2\/categories?post=632"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.switchbl8.nl\/blog\/wp-json\/wp\/v2\/tags?post=632"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}