Обратил внимание, что в логах Exim присутствуют вот такие сюжеты:
2019-07-19 07:08:51 LOGIN authenticator failed for (User) [185.137.111.23]: 535 Incorrect authentication data (set_id=alison@com.ua)
2019-07-19 07:08:51 LOGIN authenticator failed for (User) [185.137.111.123]: 535 Incorrect authentication data (set_id=staples@com.ua)
2019-07-19 07:09:00 LOGIN authenticator failed for (User) [103.231.139.130]: 535 Incorrect authentication data (set_id=blackbox@com.ua)
2019-07-19 07:09:52 LOGIN authenticator failed for (User) [185.137.111.123]: 535 Incorrect authentication data (set_id=phrases@com.ua)
2019-07-19 07:09:55 LOGIN authenticator failed for (User) [185.137.111.23]: 535 Incorrect authentication data (set_id=hahaha@com.ua)
2019-07-19 07:10:07 LOGIN authenticator failed for (User) [103.231.139.130]: 535 Incorrect authentication data (set_id=aviation@com.ua)
2019-07-19 07:10:54 LOGIN authenticator failed for (User) [185.137.111.123]: 535 Incorrect authentication data (set_id=techniques@com.ua)
2019-07-19 07:10:58 LOGIN authenticator failed for (User) [185.137.111.23]: 535 Incorrect authentication data (set_id=packard@com.ua)
2019-07-19 07:11:13 LOGIN authenticator failed for (User) [103.231.139.130]: 535 Incorrect authentication data (set_id=1254@com.ua)
.............................
2019-07-19 07:19:07 LOGIN authenticator failed for (User) [185.137.111.123]: 535 Incorrect authentication data (set_id=fester@com.ua)
2019-07-19 07:19:26 LOGIN authenticator failed for (User) [122.155.174.36]: 535 Incorrect authentication data
2019-07-19 07:19:27 LOGIN authenticator failed for (User) [185.137.111.23]: 535 Incorrect authentication data (set_id=252525@com.ua)
2019-07-19 07:20:08 LOGIN authenticator failed for (User) [103.231.139.130]: 535 Incorrect authentication data (set_id=641@com.ua)
2019-07-19 07:20:08 LOGIN authenticator failed for (User) [185.137.111.123]: 535 Incorrect authentication data (set_id=gangsta@com.ua)
2019-07-19 07:20:31 LOGIN authenticator failed for (User) [185.137.111.23]: 535 Incorrect authentication data (set_id=oscar@com.ua)
2019-07-19 07:20:46 LOGIN authenticator failed for (User) [185.234.218.126]: 535 Incorrect authentication data (set_id=feed)
2019-07-19 07:21:10 LOGIN authenticator failed for (User) [185.137.111.123]: 535 Incorrect authentication data (set_id=fucku2@com.ua)
2019-07-19 07:21:15 LOGIN authenticator failed for (User) [103.231.139.130]: 535 Incorrect authentication data (set_id=personalfinance@com.ua)
2019-07-19 07:21:35 LOGIN authenticator failed for (User) [185.137.111.23]: 535 Incorrect authentication data (set_id=brother@com.ua)
2019-07-19 07:22:11 LOGIN authenticator failed for (User) [185.137.111.123]: 535 Incorrect authentication data (set_id=freeze@com.ua)
Естественно, мне такое понравиться не могло. Хотя у взломщиков, использующих формат @com.ua и нету особых шансов, но зачем они мне будут грузить сервер?