Made a new script to handle sending an alert email if postfix is found to have crashed

check-postfix.sh

@@ -0,0 +1,106 @@
+#!/usr/bin/bash
+
+# BEGIN: Variables
+## Duration to wait to see if service has come back up
+DURATION=10
+## Wait duration to send next part of message
+WAIT=1
+
+## Test flag
+TEST=0
+
+## Email addresses
+NOTIFY_EMAIL=recipient@domain.com
+MAIL_FROM=username@domain.net
+DAMAIN=` echo $NOTIFY_EMAIL | cut -d @ -f 2 `
+
+# END: Variables
+
+
+# BEGIN: Helper Functions
+
+send_email () {
+	local MESSAGE="${1:?"send_email: No message was passed through"}"
+	sendmail $NOTIFY_EMAIL <<< "$MESSAGE"
+
+}
+
+
+: "
+The only option is to manually telnet to the smtp port on the authoritative mailserver for the target domain. As otherwise unless a mail-host is configured for email proxy, you will be unable to send an email to a user outside of the mailservers domain (without authentication). 
+"
+do_emergency_email () {
+	local MESSAGE="${1:-"The Postfix service has failed to come up on tartarus (192.168.3.2) after a service restart. Please ssh into server to troubleshoot the issues."}"
+
+	## Getting a mailserver IP for manual message
+	MAILSERVER=`dig $DOMAIN mx | grep -Eo '[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+' | head -n 1`
+
+	## Setting up coprocess to send commands to telnet session
+	coproc TELNET { telnet $MAILSERVER 25; }
+
+	## Commands to send email manually
+	local -a commands=(
+		"ehlo camtel.net\n"
+		"mail from: <$MAIL_FROM>\n"
+		"rcpt to: <$NOTIFY_EMAIL>\n"
+		"data\n"
+		"Subject: Postfix Service Failure\nFrom: $MAIL_FROM\nTo: $NOTIFY_EMAIL\n"
+		"$MESSAGE\n\n.\n"
+		"quit\n"
+	)
+
+	## Iterate through commands and send them to coprocesses
+	### We need to wait before each command as the remote mailserver will not catch everything otherwise.
+	for i in ${!commands[@]}; do
+		COMMAND="${commands[$i]}"
+		echo -e "$COMMAND" >&${TELNET[1]}
+		sleep $WAIT
+	done
+}
+
+# END: Helper Functions
+
+
+# BEGIN: Test Check 
+
+if [[ $TEST -eq 1 ]]; then
+	MESSAGE_1="
+This is a test message to verify that postfix can send an email
+"
+	send_email "$MESSAGE_1"
+
+	MESSAGE_2="This is a test email to make sure the postfix crash workaround email works"
+
+	do_emergency_email "$MESSAGE_2"
+	exit
+fi
+
+# END: Test Check
+
+
+# BEGIN: Work
+
+if [[ `systemctl is-active postfix`  != 'active' ]]; then
+	systemctl restart postfix
+
+	sleep $DURATION
+
+	SERVICE_STATUS=` systemctl is-active postfix `
+
+	if [[ "$SERVICE_STATUS" == 'active' ]]; then
+		MESSAGE="
+SUBJECT: Postfix Service Failure
+FROM: root
+TO: $NOTIFY_EMAIL
+
+The postfix service on `hostname` (`hostname -i`) was found to be not running.
+
+The service has been restarted, and after waiting $DURATION seconds it was found to be $SERVICE_STATUS.
+"
+		send_email "$MESSAGE"
+	else
+		do_emergency_email
+	fi
+fi
+
+# END: Work