Contents
Clamav(anti-virus)
1.Clam AntiVirus install
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# dnf -y install clamav clamd clamav-update |
2.Edit Clam AntiVirus configuration file
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# vi /etc/clamd.d/scan.conf ●Line 14 # Default: disabled LogFile /var/log/clamd.scan ← Uncomment ●Line 77 # Default: disabled PidFile /run/clamd.scan/clamd.pid ← Uncomment ●Line 96 # Path to a local socket file the daemon will listen on. # Default: disabled (must be specified by a user) LocalSocket /run/clamd.scan/clamd.sock ← Uncomment ●Line 219 # Run as another user (clamd must be started by root for this option to work) # Default: don't drop privileges #User clamscan ← Add # at the beginning of the line and comment it out (to make it work with root privileges) |
3.Virus definition file update settings
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# vi /etc/freshclam.conf ●Line 75 Insert a "#" at the beginning of the line "DatabaseMirror database.clamav.net" and Add "DatabaseMirror db.jp.clamav.net" #DatabaseMirror database.clamav.net DatabaseMirror db.jp.clamav.net ●Per line 151 Add "NotifyClamd /etc/clamd.d/scan.conf" #NotifyClamd /path/to/clamd.conf NotifyClamd /etc/clamd.d/scan.conf |
4.Virus definition file update
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# freshclam ClamAV update process started at Fri Dec 30 12:41:32 2022 daily database available for download (remote version: 26765) Time: 1.0s, ETA: 0.0s [========================>] 57.62MiB/57.62MiB Testing database: '/var/lib/clamav/tmp.01f21e0626/clamav-ae1f763965ce724f1616ea486bb5b09e.tmp-daily.cvd' ... Database test passed. daily.cvd updated (version: 26765, sigs: 2014567, f-level: 90, builder: raynman) main database available for download (remote version: 62) Time: 2.0s, ETA: 0.0s [========================>] 162.58MiB/162.58MiB Testing database: '/var/lib/clamav/tmp.01f21e0626/clamav-55ebadbe7472ea6e2dc50dbc77e85b42.tmp-main.cvd' ... Database test passed. main.cvd updated (version: 62, sigs: 6647427, f-level: 90, builder: sigmgr) bytecode database available for download (remote version: 333) Time: 0.3s, ETA: 0.0s [========================>] 286.79KiB/286.79KiB Testing database: '/var/lib/clamav/tmp.01f21e0626/clamav-69a9c5f45808b2e1e4498037e96948d5.tmp-bytecode.cvd' ... Database test passed. bytecode.cvd updated (version: 333, sigs: 92, f-level: 63, builder: awillia2) WARNING: Clamd was NOT notified: Can't connect to clamd through /run/clamd.scan/clamd.sock: No such file or directory |
5.Start Clam AntiVirus
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# systemctl start clamd@scan ← clamd start # systemctl enable clamd@scan ← Automatic clamd startup configuration Created symlink /etc/systemd/system/multi-user.target.wants/clamd@scan.service → /usr/lib/systemd/system/clamd@.service. # systemctl is-enabled clamd@scan enabled # systemctl status clamd@scan ← operation check ● clamd@scan.service - clamd scanner (scan) daemon Loaded: loaded (/usr/lib/systemd/system/clamd@.service; enabled; vendor pr> Active: active (running) since Fri 2022-12-30 13:58:57 JST; 54s ago Docs: man:clamd(8) man:clamd.conf(5) https://www.clamav.net/documents/ Main PID: 859 (clamd) Tasks: 2 (limit: 21862) Memory: 1.4G CPU: 33.264s CGroup: /system.slice/system-clamd.slice/clamd@scan.service mq859 /usr/sbin/clamd -c /etc/clamd.d/scan.conf Dec 30 13:58:57 Lepard clamd[859]: Portable Executable support enabled. Dec 30 13:58:57 Lepard clamd[859]: ELF support enabled. Dec 30 13:58:57 Lepard clamd[859]: Mail files support enabled. Dec 30 13:58:57 Lepard clamd[859]: OLE2 support enabled. Dec 30 13:58:57 Lepard clamd[859]: PDF support enabled. Dec 30 13:58:57 Lepard clamd[859]: SWF support enabled. Dec 30 13:58:57 Lepard clamd[859]: HTML support enabled. Dec 30 13:58:57 Lepard clamd[859]: XMLDOCS support enabled. Dec 30 13:58:57 Lepard clamd[859]: HWP3 support enabled. Dec 30 13:58:57 Lepard clamd[859]: Self checking every 600 seconds. |
6.Conduct virus scan
■Download a test virus and perform a virus scan
■Download a test virus and perform a virus scan
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# wget http://www.eicar.org/download/eicar.com # clamscan --infected --remove --recursive /root/eicar.com: Win.Test.EICAR_HDB-1 FOUND ← Virus detection /root/eicar.com: Removed ← Virus Removal ----------- SCAN SUMMARY ----------- Known viruses: 8646533 Engine version: 0.103.7 Scanned directories: 1 Scanned files: 11 Infected files: 1 Data scanned: 0.03 MB Data read: 0.02 MB (ratio 2.00:1) Time: 32.654 sec (0 m 32 s) Start Date: 2022:12:30 14:00:42 End Date: 2022:12:30 14:01:15 |
7.Virus scan auto-execute script
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# mkdir -p /var/www/system # cd /var/www/system Create clamscan.sh in /var/www/system with the following contents # vi /var/www/system/clamscan.sh #!/bin/bash PATH=/usr/bin:/bin # excludeopt setup excludelist=/var/www/system/clamscan.exclude if [ -s $excludelist ]; then for i in `cat $excludelist` do if [ $(echo "$i"|grep \/$) ]; then i=`echo $i|sed -e 's/^\([^ ]*\)\/$/\1/p' -e d` excludeopt="${excludeopt} --exclude-dir=$i" else excludeopt="${excludeopt} --exclude=$i" fi done fi # signature update freshclam # virus scan clamscan --recursive --remove ${excludeopt} / |
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# chmod 700 clamscan.sh |
8.Virus scan exclusion directory settings
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# echo "/sys/" >> /var/www/system/clamscan.exclude # echo "/proc/" >> /var/www/system/clamscan.exclude |
The sys and proc directories are excluded.
9.Scheduled virus scan execution
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# crontab -e 0 1 * * * /var/www/system/clamscan.sh > /dev/null 2>&1 |
10.Run a trial script and do a full scan (takes a while)
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# /var/www/system/clamscan.sh |
Mail Server Installation
1. Postfix
1.1 Install
Install Postfix and build an SMTP server
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# dnf -y install postfix |
Make sure Postfix is installed
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# rpm -qa | grep postfix postfix-3.5.9-19.el9.x86_64 postfix-perl-scripts-3.5.9-19.el9.x86_64 pcp-pmda-postfix-5.3.7-7.0.2.el9.x86_64 |
1.2 Register Postfix to the service
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# systemctl enable postfix.service Created symlink /etc/systemd/system/multi-user.target.wants/postfix.service → /usr/lib/systemd/system/postfix.service. # systemctl is-enabled postfix.service enabled |
1.3 Backup postfix configuration files, main.cf and master.cf files
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# cp -p /etc/postfix/main.cf `date '+/etc/postfix/main.cf.%Y%m%d'` # cp -p /etc/postfix/master.cf `date '+/etc/postfix/master.cf.%Y%m%d'` |
1.4 Edit postfix configuration file
To prevent unauthorized mail relay, configure Postfix to require authentication for outgoing mail as well, using Dovecot's SASL function.
To prevent unauthorized mail relay, configure Postfix to require authentication for outgoing mail as well, using Dovecot's SASL function.
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# vi /etc/postfix/main.cf ●Added around line 96 #myhostname = virtual.domain.tld myhostname = mail.<domain> ●Add your domain name around line 103 #mydomain = domain.tld mydomain = <domain> ●Uncomment out per line 118 myorigin = $mydomain ●Change per line 135 inet_interfaces = all ●Comment out around line 183 and add to line 184. #mydestination = $myhostname, localhost.$mydomain, localhost mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain ●Added around line 287 #mynetworks = 168.100.189.0/28, 127.0.0.0/8 #mynetworks = $config_directory/mynetworks #mynetworks = hash:/etc/postfix/network_table mynetworks = 192.168.11.0/24, 127.0.0.0/8 ←192.168.11.0/24 to suit your environment ●Uncomment per line 440 Set the mail storage format. #home_mailbox = Mailbox home_mailbox = Maildir/ ●Added around line 447 #mail_spool_directory = /var/mail mail_spool_directory = /var/spool/mail ●Added around line 593 #smtpd_banner = $myhostname ESMTP $mail_name #smtpd_banner = $myhostname ESMTP $mail_name ($mail_version) smtpd_banner = $myhostname ESMTP unknown ●Add the following to the last line # Limit send/receive mail size to 10M message_size_limit = 10485760 # Limit mailbox size to 1G mailbox_size_limit = 1073741824 # SMTP-Auth Settings smtpd_sasl_type = dovecot smtpd_sasl_path = private/auth smtpd_sasl_auth_enable = yes smtpd_sasl_security_options = noanonymous smtpd_sasl_local_domain = $mydomain smtpd_recipient_restrictions = permit_mynetworks, permit_auth_destination, permit_sasl_authenticated, reject |
Release SMTP port (port 25)
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# firewall-cmd --add-service=smtp --permanent success # firewall-cmd --reload success |
1.5 Start Postfix
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# systemctl enable --now postfix |
2.Dovecot
2.1 dovecot install
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# dnf -y install dovecot |
2.2 Edit dovecot.conf file
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# cp -p /etc/dovecot/dovecot.conf `date '+ /etc/dovecot/dovecot.conf.%Y%m%d'` # vi /etc/dovecot/dovecot.conf ●Add around line 25 # protocols = imap pop3 lmtp protocols = imap pop3 ●Line 30 : Uncomment # Remove [::] if listening for IPv4 only listen = *, :: |
2.3 Edit 10-auth.conf file
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# vi /etc/dovecot/conf.d/10-auth.conf ●Line 10 : Uncomment and change If plain text authentication is also allowed disable_plaintext_auth = no ●Line 100 : Add auth_mechanisms = plain login |
2.4 Edit 10-mail.conf file
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# vi /etc/dovecot/conf.d/10-mail.conf ●Line 31 : Add mail_location = maildir:~/Maildir |
2.5 Edit 10-master.conf file
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# vi /etc/dovecot/conf.d/10-master.conf ●Lines 107-109 : Uncomment and add # Postfix smtp-auth unix_listener /var/spool/postfix/private/auth { mode = 0666 user = postfix group = postfix } |
2.6 Edit 10-ssl.conf file
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# vi /etc/dovecot/conf.d/10-ssl.conf ●Per line 8 Change "ssl = required" to "ssl = yes" ssl = yes |
2.7 Register dovecot as a service and start
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# systemctl enable dovecot.service Created symlink /etc/systemd/system/multi-user.target.wants/dovecot.service → /usr/lib/systemd/system/dovecot.service. # systemctl is-enabled dovecot.service Enabled # systemctl start dovecot.service |
2.8 Permission port opening for POP/IMAP service with firewalld
POP is [110/TCP], IMAP is [143/TCP].
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# firewall-cmd --permanent --add-service=pop3 # firewall-cmd --permanent --add-service=imap # firewall-cmd --reload |
3.Create mail user and check operation
3.1 advance preparation
①Pretreatment for new users
When a new user is added, set up the system to automatically send and receive e-mail.
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# mkdir -p /etc/skel/Maildir/{new,cur,tmp} # chmod -R 700 /etc/skel/Maildir/ # echo "~/Maildir/"> /etc/skel/.forward # chmod 600 /etc/skel/.forward |
Configure the already created users to be able to send and receive e-mail.
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# mkdir -p /home/huong/Maildir/{new,cur,tmp} # chown -R huong:huong /home/huong/Maildir/ # chmod 700 /home/huong/Maildir # chmod 700 /home/huong/Maildir/{new,cur,tmp} |
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Mail client installation # dnf -y install s-nail # echo 'export MAIL=$HOME/Maildir' >> /etc/profile.d/mail.sh Add user [linux] # useradd linux # passwd linux Changing password for user linux. New password: Retype new password: passwd: all authentication tokens updated successfully. |
3.3 Operation check ①
Log in as an email user and send a test email.
Log in as an email user and send a test email.
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# su - linux $ mail linux@localhost Subject: Test Mail To: linux@localhost mail test ^D ------- (Preliminary) Envelope contains: To: linux@localhost Subject: Test Mail Send this message [yes/no, empty: recompose]? y $ mail s-nail version v14.9.22. Type `?' for help /home/linux/Maildir: 1 message 1 new ?N 1 linux@korodes.com 2022-12-30 14:44 19/524 "Test Mail " & 1 [-- Message 1 -- 19 lines, 524 bytes --]: Date: Fri, 30 Dec 2022 14:44:54 +0900 To: linux@localhost Subject: Test Mail Message-Id: <20221230054454.2E37411F5847@mail.korodes.com> From: linux@korodes.com test mail . D & Enter "q" to exit |
3.4 Operation check ②.
Set up and confirm your account in Mozilla Thunderbird. This time we will set it up with the general user "huong".
Set up and confirm your account in Mozilla Thunderbird. This time we will set it up with the general user "huong".
①Start Thunderbird
Your full name : Any name
Email addtess : huong@korodes.com
Password : Password for huong
and click "Configure manually".
➁Set "INCOMMING SERVER" and "OUTGOING SERVER" as shown below and click "Re-test".
➂The following settings were found by probinfg the given server
After clicking "Done," the following "Warning" appears, but there is no problem, so click "Confirm"
④Click "Finish" when "Account syccessfuly created" is displayed.
Mail server : Postfix + Clamav + Amavisd+SpamAssassin
1.Real-time scanning of e-mails
①Install Amavisd and Clamav Server
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# dnf config-manager --set-enabled ol9_codeready_builder # dnf install https://dl.fedoraproject.org/pub/epel/epel-release-latest-9.noarch.rpm # dnf config-manager --set-enabled epel # dnf -y install amavisd-new clamd perl-Digest-SHA1 perl-IO-stringy |
➁Configuration File Editing
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# vi /etc/clamd.d/scan.conf ●Line 77: Change PidFile /var/run/clamd.scan/clamd.pid ●Line 81: Uncomment TemporaryDirectory /var/tmp ●Line 96: Change LocalSocket /var/run/clamd.scan/clamd.sock |
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# touch /var/log/clamd.scan # chown clamscan. /var/log/clamd.scan # systemctl enable clamd@scan |
➂Setup and start Amavisd
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# vi /etc/amavisd/amavisd.conf ●Delete # at the beginning of the line per line 13 @bypass_spam_checks_maps = (1); # controls running of anti-spam code ● Line 23: Change to own domain name $mydomain = 'domain name'; ●Comment out per line 28 #$QUARANTINEDIR = undef; # -Q ●Comment out per line 125 # $virus_admin = undef; # notifications recip ●Line 158: Uncomment and change to own host name $myhostname = 'mail.domain name'; # systemctl start amavisd # systemctl enable amavisd Created symlink /etc/systemd/system/multi-user.target.wants/amavisd.service → /usr/lib/systemd/system/amavisd.service. |
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# vi /etc/postfix/main.cf # Add to the last line content_filter=smtp-amavis:[127.0.0.1]:10024 # vi /etc/postfix/master.cf # Add to the last line smtp-amavis unix - - n - 2 smtp -o smtp_data_done_timeout=1200 -o smtp_send_xforward_command=yes -o disable_dns_lookups=yes 127.0.0.1:10025 inet n - n - - smtpd -o content_filter= -o local_recipient_maps= -o relay_recipient_maps= -o smtpd_restriction_classes= -o smtpd_client_restrictions= -o smtpd_helo_restrictions= -o smtpd_sender_restrictions= -o smtpd_recipient_restrictions=permit_mynetworks,reject -o mynetworks=127.0.0.0/8 -o strict_rfc821_envelopes=yes -o smtpd_error_sleep_time=0 -o smtpd_soft_error_limit=1001 -o smtpd_hard_error_limit=1000 |
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# systemctl restart postfix |
⑤Check with Thunderbird
I sent a test email to myself in Thunderbird, and in the header display part of the received email, I see the following
"X-Virus-Scanned: amavisd-new at korodes."
"X-Virus-Scanned: amavisd-new at korodes."
2.Email spam protection
①SpamAssassin installed to prevent spam
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# dnf -y install spamassassin spamass-milter-postfix # systemctl start spamassassin # systemctl enable spamassassin Created symlink /etc/systemd/system/multi-user.target.wants/spamassassin.service → /usr/lib/systemd/system/spamassassin.service. |
②SpamAssassin Settings
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# vi /etc/mail/spamassassin/v310.pre ●Delete # at the beginning of the line per line 24 loadplugin Mail::SpamAssassin::Plugin::DCC |
③SpamAssassin configuration file modernization script
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# cd /var/www/system # vi /var/www/system/spamassassin-update.sh #!/bin/bash cd /etc/mail/spamassassin wget -q https://github.com/kittyfreak/spamassassin_user_prefs/archive/refs/heads/main.zip [ $? -ne 0 ] && exit unzip main.zip >/dev/null 2>&1 [ $? -ne 0 ] && exit rm -f main.zip mv spamassassin_user_prefs-main/user_prefs . rm -rf spamassassin_user_prefs-main diff user_prefs user_prefs.org > /dev/null 2>&1 if [ $? -ne 0 ]; then cp user_prefs local.cf echo "report_safe 0" >> local.cf echo "rewrite_header Subject ***SPAM***" >> local.cf # Restart SpamAssassin if [ -f /etc/rc.d/init.d/spamassassin ]; then /etc/rc.d/init.d/spamassassin restart > /dev/null else systemctl restart spamassassin > /dev/null fi fi cp user_prefs user_prefs.org |
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# chmod 700 /var/www/system/spamassassin-update.sh # /var/www/system/spamassassin-update.sh |
Check that the SpamAssassin configuration file is created in the /etc/mail/spamassassin directory with the date of the day.
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# ls -l /etc/mail/spamassassin total 1620 drwxr-xr-x 2 root root 40 Dec 30 16:08 channel.d -rw-r--r-- 1 root root 1194 May 6 2022 init.pre -rw-r--r-- 1 root root 499337 Dec 30 16:27 local.cf drwx------ 2 root root 6 May 6 2022 sa-update-keys -rw-r--r-- 1 root root 62 May 6 2022 spamassassin-default.rc -rwxr-xr-x 1 root root 39 May 6 2022 spamassassin-helper.sh -rw-r--r-- 1 root root 55 May 6 2022 spamassassin-spamc.rc -rw-r--r-- 1 root root 499289 Dec 29 2021 user_prefs -rw-r--r-- 1 root root 499289 Dec 30 16:27 user_prefs.org -rw-r--r-- 1 root root 2523 Dec 30 16:25 v310.pre -rw-r--r-- 1 root root 1194 May 6 2022 v312.pre -rw-r--r-- 1 root root 2416 May 6 2022 v320.pre -rw-r--r-- 1 root root 1237 May 6 2022 v330.pre -rw-r--r-- 1 root root 1020 May 6 2022 v340.pre -rw-r--r-- 1 root root 1309 May 6 2022 v341.pre -rw-r--r-- 1 root root 1469 May 6 2022 v342.pre -rw-r--r-- 1 root root 1264 May 6 2022 v343.pre |
Set up cron to automatically run a script daily that updates the SpamAssassin configuration file
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# crontab -e 0 2 * * * /var/www/system/spamassassin-update.sh > /dev/null 2>&1 |
④Integrate SpamAssassin into Postfix
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# vi /etc/postfix/master.cf ●Add "#" to the beginning of line 11 and add SpamAssassin setting to line 12 # smtp inet n - n - - smtpd smtp inet n - n - - smtpd -o content_filter=spamassassin ●Add to last line smtp-amavis unix - - n - 2 smtp -o smtp_data_done_timeout=1200 -o smtp_send_xforward_command=yes -o disable_dns_lookups=yes 127.0.0.1:10025 inet n - n - - smtpd -o content_filter= -o local_recipient_maps= -o relay_recipient_maps= -o smtpd_restriction_classes= -o smtpd_client_restrictions= -o smtpd_helo_restrictions= -o smtpd_sender_restrictions= -o smtpd_recipient_restrictions=permit_mynetworks,reject -o mynetworks=127.0.0.0/8 -o strict_rfc821_envelopes=yes -o smtpd_error_sleep_time=0 -o smtpd_soft_error_limit=1001 -o smtpd_hard_error_limit=1000 spamassassin unix - n n - - pipe user=nobody argv=/usr/bin/spamc -e /usr/sbin/sendmail.postfix -oi -f ${sender} ${recipient} |
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# systemctl restart postfix |
⑥If you send an e-mail to yourself in Thunderbird with the following information in the body, the following will appear in the header.
「XJS*C4JDBQADN1.NSBN3*2IDNEN*GTUBE-STANDARD-ANTI-UBE-TEST-EMAIL*C.34X」
