Customer had an issue in the AR1220E configuration, with an ACL rule blocking the SMTP service, SMTP port couldn’t be forwarded.
1. After analyzing the configuration from the AR1220E, we have discovered that a NAT outbound using the following ACL rule: "rule 5 permit" was set on the inside port. On the same port, was also configured the following command : "nat server protocol tcp global current-interface smtp inside x.x.x.x smtp".
2. We advised the customer to remove the NAT outbound configuration from the inside port and afterwards the SMTP communication was successful.
NAT outbound configuration was set on the inside port.
Removed the NAT outbound configuration from the inside port and afterwards the SMTP communication was successful.