In the program web interface window, select the Settings → Built-in MTA → Basic Settings section.
In the Domain name text box, type the domain name of Kaspersky Secure Mail Gateway (mydomain) that all cluster nodes will share.
If you want each cluster node to use its own fully qualified domain name (myhostname), set the Use FQDN of cluster nodes toggle switch to Enabled.
In the Hostname text box, type the full domain name of Kaspersky Secure Mail Gateway (myhostname).
The text box is accessible only if the Use FQDN of cluster nodes option is turned off.
In the Message size limit (bytes) field, specify the maximum size of an email message including SMTP headers that can be forwarded through Kaspersky Secure Mail Gateway (message_size_limit), in bytes.
Specify 0 if no limit is required.
The default value is 20971520 bytes (20 MB).
Create a list of trusted networks and network hosts that are allowed to send email messages via Kaspersky Secure Mail Gateway (mynetworks). To do so, enter the host IP addresses and/or network addresses in CIDR format in the Trusted networks field and press ENTER.
As a rule, these are internal networks and network hosts of your organization. For example, you can specify the IP addresses of Microsoft Exchange servers used at your organization.
You can type addresses one by one or paste a whole list of semicolon-separated networks.
If trusted networks are not specified, Kaspersky Secure Mail Gateway will not be receiving messages from internal mail servers and redirect them outside the network of your organization.
In the Email destination address field, type the address and port of your edge gateway (relayhost). Kaspersky Secure Mail Gateway will be redirecting all messages to this address.
You can enter an IPv4 address (for example, 192.168.0.1), domain name, or FQDN, or you can leave the field empty. If the value of this field is not specified, Kaspersky Secure Mail Gateway uses your DNS server settings for routing email.
If you have configured email routing for individual domains, Kaspersky Secure Mail Gateway will be redirecting email messages to the addresses specified for each domain.
If in the Email destination address field, you entered a domain name or a FQDN, you can enable MX record lookup for the specified domain name. To do so, move the MX lookup toggle switch to the Enabled position.