> On 15 Dec 2016, at 14:56, L.P.H. van Belle <be...@bazuin.nl> wrote: > > Now the thing i dont get. > > 1) if both ipnumbers have a hostname, why do i see : unknown[1.2.3.4]
Your starting assumption is wrong or mistaken. If the postfix logs are saying "unknown[1.2.3.4]” it means reverse lookups of that IP address are not returning a hostname. You appear to have chosen to obscure the actual IP address and very probably the real domain names in the SMTP envelope (ie “helo==...”, etc) as well. So nobody here will be able to explain what is wrong or how to fix it. This might be a DNS misconfiguration. Or it might be a fault in some locally deployed hostname-to-address mechanism like /etc/hosts or Active Directory or NIS(+) or... > 2) are Round Robin A record for mail Allowed. Yes. Of course. It’s very common for domains to have >1 IP address to handle inbound mail, particularly on busy mail services. For instance at the moment there are 70+ IP addresses handling incoming mail for hotmail.com. yahoo.com is currently advertising 24 IP addresses for inbound SMTP.
