iptables -A OUTPUT -p tcp -m tcp --sport 25 -j REJECT --reject-with icmp-port-unreachable
SMTP -> ERROR: Failed to connect to server: Unable to find the socket transport "ssl" - did you forget to enable it when you configured PHP? (0)
SMTP Error: Could not connect to SMTP host.
$ /opt/php53/bin/php -i | grep -i openssl
SSL Version => OpenSSL/1.0.2l
OpenSSL support => disabled (install ext/openssl)