Hi there, it's a long time ago, I needed help (your tutorials are too good), but now I cannot get rid of a big Problem. No matter what I do, our mailserver IP gets blocked over and over again by Hotmail and AOL. I got a server from Hetzner and followed the tutorial "perfect-server-ubuntu-16.04-with-apache-php-myqsl-pureftpd-bind-postfix-doveot-and-ispconfig". IPv4 and IPv6 are both in use and Reverse-DNS for both is set as "mail.serverdomain.de". My config so far seem to be ok - for me (put it in as attachement). I've put on a real Wildcard-SSL-cert and use it in dovecot/postfix. I've put on DKIM with default-selector for every maildomain as follows: Code: for serverdomain = "default._domainkey.serverdomain.de. 3600 TXT v=DKIM;t=s;p=..." for maildomain1 = "default._domainkey.maildomain1.de. 3600 TXT v=DKIM;t=s;p=..." Then, because I use my provider as DNS/Nameserver, I have put on records for every domain (serverdomain, maildomain1, ...) as follows: Code: serverdomain.de A xxx.xxx.xxx.xxx serverdomain.de AAAA xxx:xxx:xxx:xxx serverdomain.de TXT v=spf1 mx a ip4:xxx.xxx.xxx.xxx ip6:xxx:xxx:xxx:xxx ~all default._domainkey.serverdomain.de TXT v=DKIM1; t=s; p=... _dmarc.serverdomain.de TXT v=DMARC1; p=none; rua=mailto:[email protected][email protected] Everything looks ok to me and tests by mxtoolbox.com and other run well. However, there are bot-mailings going on, just using old aliases or existing mailadresses from my server (with different IPs of course), that get blocked by AOL users and so our server IP right now is blocked all the time (shouldn't be possible, but I guess, maybe the adress-blockings by AOL users are influencing AOLs RBL block behavior ?). Any idea what I could change or maybe even correct in my config or what I could do to get this working again? My contact with the postmaster from AOL doesn't do anything exept getting the message that we are blocked. Every mail is returned as follows: Code: host mailin-04.mx.aol.com[188.8.131.52] refused to talk to me: 554- (RTR:BL) https://postmaster.aol.com/error-codes#554rtrbl 554 Hotmail is even worse...you don't get any mail back.