In certain circumstances, the error message can occur when attempting to send or receive mail via F-Secure Internet Gatekeeper for Linux (FSIGK).
SMTP transfer denied is a common issue mainly because e-mail recipient domains are restricted on the server concerned. For the most part, this is a consequence of the huge quantities of spam flooding e-mail networks.
Note: This article assumes deep technical understanding of F-Secure's products, network protocols and the relevant operating system. If you are unsure, contact F-Secure support for assistance.
To ensure e-mail delivery, do as follows:
If you receive e-mail messages from the Internet to specific domains, on the SMTP proxy page, specify the domains in Restrict e-mail recipients.
If you send e-mail messages from internal machines and transfer from specific clients is needed, specify the connecting client as Hosts and networks within LAN and enable the LAN access settings section.
Note: If connecting addresses are translated by NAT, the address connecting to FSIGK must be specified. The connecting address can be seen in the access.log file.
If connection from all hosts in the 192.168.x.x subnet should be allowed, do as follows: