The SMTP server is the server responsible for forwarding emails. The process for which an email is sent to the outside (ie to a different mail server) is called RELAY. Mail relay is very dangerous as a relay server can also be used maliciously for sending spam.
Almost all the connectivity providers that once provided this service, authenticating the user on the connection IP, are slowly ceasing the provision of this service.
Our organization provides the SMTP relay service included with all our hosting plans. This type of service authenticates the user based on the POP / IMAP login credentials (ie the login credentials of the mail unloading server). Therefore on the mail client it is always necessary to check the "server authentication required" option on the outgoing mail server.
Access to the mail relay server is regulated by a special policy server which allows the regulation of outgoing mail. The policy server is configured to give maximum security to the customer and to guarantee, among other things, that in case of abuse of their mailbox by viruses installed on their computer or other malicious scripts, their mailbox is not used for send spam.
The maximum standard daily sending rate is 300 mails per day for each relay user. This rate is calculated only on relay emails, that is directed to users outside the local network. When the installment is reached, no further mail is allowed. An internal system analyzes whether the limit is reached for reasons of use or there has been a malicious activity, perhaps generated by an abused script or another.
If an anomalous mail is detected (for example due to spam) a ticket is opened on the customer to warn him of this.
If the customer needs, for work reasons, an out-of-standard delivery rate, please contact us via ticket on https://www.denali.eu indicating the volume you plan to make and the frequency of mailings. The reason for such submission must also be specified.
For consistent sending volumes we suggest however to activate a special Relay personal VPS, which allows a more systematic use of the relay, even with much larger volumes and also allows a thorough check of the mailserver queue.