I am using a Debian Jessie server and have setup exim4 to send me emails instead of postfix or sendmail. Thats when I started getting loads of emails as follows:First:Title: * SECURITY information for vultr.guest * Body: vultr.guest: Dec  7 12:13:29 : root : unable to resolve host vultr.guestSecond:Title: Cron  test -x /etc/init.d/sendmail && /usr/share/sendmail/sendmail cron-mspBody:This is an automatically generated Delivery Status NotificationTHIS IS A WARNING MESSAGE ONLY.YOU DO NOT NEED TO RESEND YOUR MESSAGE.Delivery to the following recipient has been delayed:     root@example.comMessage will be retried for 2 more day(s)Technical details of temporary failure:The recipient server did not accept our requests to connect. Learn more at https://support.google.com/mail/answer/7720[(10) example.com. [xxx.xxx.xxx.90]:25: socket error]----- Original message -----DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;        d=gmail.com; s=20120113;        h=from:to:subject:mime-version:content-type:content-transfer-encoding         :message-id:date;        bh=k/8GlT8DBvBIJzBOOfw8qR0kGPzj7m9ZR/aj+JOKBhg=;        b=eA6kpVtS0eNBO0CFBfLzlnaYwZ9/GubMaWTGUkG4MaxbNy55YxY2jZAuh3RHI2mo8Q         qp5OmKihchYTgCxcAx0xvJaXuuxDhoT9dCJ6YEIzqjmypWjpUEqoXkNu7uKU4Cd1vTfS         5/dSvE7zVE6TYe4L18vrOiYBEUNrJQ3lTdv//RrlHZs/f62GorIyMHgVL4XvkVNLWF/K         lK9SSybf9ee3KTKUxurBm1Tyah62Gk4/869Hynr1QEAjSAzM8sSKDyKH/KOZ06sDWtPQ         jE0Agxffk8RkhsFkEtIbpZBfS/zagGZ8+CXsGqR9541ylMAHGOGeYtRp4oiB8tVP2Sbv         h4Rw==X-Received: by 10.129.114.10 with SMTP id n10mr3081975ywc.0.1449600002717;        Tue, 08 Dec 2015 10:40:02 -0800 (PST)Return-Path: <myEmailAddress@gmail.com>Received: from vultr.guest ([104.156.246.90])        by smtp.gmail.com with ESMTPSA id f203sm2998216ywf.45.2015.12.08.10.40.02        for <root@example.com>        (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);        Tue, 08 Dec 2015 10:40:02 -0800 (PST)From: Cron Daemon <myEmailAddress@gmail.com>X-Google-Original-From: root@example.com (Cron Daemon)Received: from smmsp by vultr.guest with local (Exim 4.84)        (envelope-from <smmsp@example.com>)        id 1a6NBB-0007Vu-Os        for root@example.com; Tue, 08 Dec 2015 13:40:01 -0500To: root@example.comSubject: Cron <smmsp@vultr> test -x /etc/init.d/sendmail && /usr/share/sendmail/sendmail cron-mspMIME-Version: 1.0Content-Type: text/plain; charset=UTF-8Content-Transfer-Encoding: 8bitX-Cron-Env: <MAILTO=root>X-Cron-Env: <SHELL=/bin/sh>X-Cron-Env: <HOME=/var/lib/sendmail>X-Cron-Env: <PATH=/usr/bin:/bin>X-Cron-Env: <LOGNAME=smmsp>Message-Id: <E1a6NBB-0007Vu-Os@vultr.guest>Date: Tue, 08 Dec 2015 13:40:01 -0500I edited /etc/cron.d/sendmail and first tried to change the MAILTO= line from root to my gmail address. That did not help. So I commented that line out, and the */20 *    *    *    *       smmsp   test -x /etc/init.d/sendmail && /usr/share/sendmail/sendmail cron-mspThat made it stop from sending me emails every 20 minutes with junk. But I still get many and often emails with the Subject: * SECURITY information for vultr.guest *Body: This is an automatically generated Delivery Status NotificationTHIS IS A WARNING MESSAGE ONLY.YOU DO NOT NEED TO RESEND YOUR MESSAGE.Delivery to the following recipient has been delayed:     root@example.comMessage will be retried for 1 more day(s)Technical details of temporary failure:The recipient server did not accept our requests to connect. Learn more at https://support.google.com/mail/answer/7720[(10) example.com. [xxx.xxx.xxx.90]:25: socket error]I did modify /etc/hostname and removed vultr.guest and replaced it with example.com. And in /etc/hosts I only have:127.0.0.1   localhost127.0.1.1   install.install install# The following lines are desirable for IPv6 capable hosts::1     localhost ip6-localhost ip6-loopbackff02::1 ip6-allnodesff02::2 ip6-allroutersWhat did I configure wrong? And how can I fix it?UPDATE: The /etc/exim4/update-exim4.conf.conf contents are:dc_eximconfig_configtype='satellite'dc_other_hostnames=''dc_local_interfaces='127.0.0.1 ; ::1'dc_readhost=''dc_relay_domains=''dc_minimaldns='false'dc_relay_nets=''dc_smarthost='smtp.gmail.com::587'CFILEMODE='644'dc_use_split_config='false'dc_hide_mailname='true'dc_mailname_in_oh='true'dc_localdelivery='mail_spool'
Delivery Status Notification (Delay) emails from my server?
debian;email;exim
It seems to me that VULTR's tutorial is not correct. When you configure exim4 by dpkg-reconfigure exim4-config, they tell you to choose mail sent by smarthost; no local mail, and configure it as follows: System mail name: YOUR_HOSTNAMEIP-addresses to listen on for incoming SMTP connections: 127.0.0.1 ; ::1Other destinations for which mail is accepted: <BLANK>Visible domain name for local users: <BLANK>IP address or host name of the outgoing smarthost: smtp.gmail.com::587Keep number of DNS-queries minimal (Dial-on-Demand)? NoSplit configuration into small files? NoRoot and postmaster mail recipient: <BLANK>But I doubt that the Other destinations for which mail is accepted: should be BLANK. If you configure it, add your email address, or your example.com domain/email. Otherwise, try to edit the following locations:/etc/aliases:root: address@example.commailer-daemon: address@example.compostmaster: address@example.comnobody: address@example.comhostmaster: address@example.comusenet: address@example.comnews: address@example.comwebmaster: address@example.comwww: address@example.comwww-data: address@example.comftp: address@example.comabuse: address@example.comnoc: address@example.comsecurity: address@example.com*: address@example.comand edit /etc/email-addresses to include the user:email combo: root: address@example.commail: address2@example2.com*: address@example.comThen restart service sendmail restart and service exim4 restartHope it helps