There is a main domain domen.ru hosted by 1.1.1.1, created a subdomain app.domen.ru - it posted mailWizz , transactional emails sent from this server.
Also, there are 10 servers, each with 10 ip: (2.2.2.2 - 102.102.102.102). On the main server 100 1.1.1.1 create subdomains and sending each...