On a debian wheezy mailserver with postfix an courier I want to whitelist certain IPs, that are blocked somehow (those IPs are from an openvpn provider) so I can send out mails with that server.
I already tried to remove temporarily all reject rules in
/etc/postfix/main.cf and restarted postfix, but I was still blocked to send mails.
If I don't use another VPN exit, sending mails works fine with Thunderbird.
Where else can I search for the reason, I am blocked?
I use STARTTLS on port 587 to send out mails.