# apt install msmtp
# cat /etc/msmtprc
defaults
port 25
tls off
#tls on
auth off
account default
host mail.isp.un
domain server.corpX.un
#from asterisk@server.corpX.un #need for mutt
#host server.corpX.un
#domain corpX.un
#from root@lan.corpX.un
$ cat mail.txt
Content-Type: text/plain; charset=UTF-8
To: userX@isp.un
From: Asterisk
Subject: Record
Запись
cделана
cat mail.txt | msmtp -f asterisk@server.corpX.un userX@isp.un