Hi,
I'm getting exhausted with my new Exchange 2013, I Installed it as CAS and Mailbox role on a new server, everything is fine, it was integrated well with my DC, publish it on Internet (MX pointing), people also can send/receive email, but the problem is the SPAM, i checked my server at mxtoolbox.com and I found the the SMTP Open Relay - May be an open relay. I test telnet from outside to my exchange server using port 25, and I found this message:
220 xxxxxxxxxxxxx.com Microsoft ESMTP MAIL Service ready at Wed, 12 Nov 2014 00:22:13 +0700
then I try to configure POP configuration in outlook client and SMTP server using the Port 25, and it can send email, and now google start blocking our domain, I tried to find any article regarding this issue, but couldn't find the solution
fyi, the receive connector is still default and only add the send connector using the microsoft reference.
anyone can help me? pls. can I block the Port 25? tried it already, the email from other external domain is stop coming.
thx