Contents
Install clamav ( anti-virus software )
1.Clam AntiVirus Install
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# dnf -y install clamav clamd clamav-update |
2.Clam AntiVirus Configuration File Editing
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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) |
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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 |
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# freshclam ClamAV update process started at Wed Jun 8 17:09:20 2022 daily database available for download (remote version: 26565) Time: 3.0s, ETA: 0.0s [========================>] 56.03MiB/56.03MiB Testing database: '/var/lib/clamav/tmp.aca2d3f1fa/clamav-23517084062dbf640a1e7db5635d12b5.tmp-daily.cvd' ... Database test passed. daily.cvd updated (version: 26566, sigs: 1985565, f-level: 90, builder: raynman) main database available for download (remote version: 62) Time: 7.9s, ETA: 0.0s [========================>] 162.58MiB/162.58MiB Testing database: '/var/lib/clamav/tmp.aca2d3f1fa/clamav-31ab0225aac64a6d935b73fa24c3b497.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: 0.5s, ETA: 0.0s [========================>] 286.79KiB/286.79KiB Testing database: '/var/lib/clamav/tmp.aca2d3f1fa/clamav-20ea46288aefc5e6fb938184abb83e92.tmp-bytecode.cvd' ... Database test passed. bytecode.cvd updated (version: 333, sigs: 92, f-level: 63, builder: awillia2) |
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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 pres> Active: active (running) since Fri 2022-07-15 19:55:41 JST; 19s ago Docs: man:clamd(8) man:clamd.conf(5) https://www.clamav.net/documents/ Main PID: 4230 (clamd) Tasks: 2 (limit: 11187) Memory: 1.2G CGroup: /system.slice/system-clamd.slice/clamd@scan.service mq4230 /usr/sbin/clamd -c /etc/clamd.d/scan.confJul 15 19:55:41 Alma clamd[4230]: ELF support enabled. Jul 15 19:55:41 Alma clamd[4230]: Mail files support enabled. Jul 15 19:55:41 Alma clamd[4230]: OLE2 support enabled. Jul 15 19:55:41 Alma clamd[4230]: PDF support enabled. Jul 15 19:55:41 Alma clamd[4230]: SWF support enabled. Jul 15 19:55:41 Alma clamd[4230]: HTML support enabled. Jul 15 19:55:41 Alma clamd[4230]: XMLDOCS support enabled. Jul 15 19:55:41 Alma clamd[4230]: HWP3 support enabled. |
■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 /root/eicar.com: Removed. ----------- SCAN SUMMARY ----------- Known viruses: 8622184 Engine version: 0.103.6 Scanned directories: 1 Scanned files: 10 Infected files: 1 Data scanned: 0.02 MB Data read: 0.01 MB (ratio 2.00:1) Time: 35.277 sec (0 m 35 s) Start Date: 2022:07:15 19:57:42 End Date: 2022:07:15 19:58:17 |
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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 # echo "/sys/" >> /var/www/system/clamscan.exclude # echo "/proc/" >> /var/www/system/clamscan.exclude Exclude sys and proc directories. |
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# crontab -e 0 1 * * * /var/www/system/clamscan.sh > /dev/null 2>&1 |
Mail Server Installation
1.Postfix Installation
1.1 Install
Install Postfix and build an SMTP server
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# dnf -y install postfix |
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# rpm -qa | grep postfix pcp-pmda-postfix-5.3.5-8.el8.x86_64 postfix-3.5.8-4.el8.x86_64 postfix-perl-scripts-3.5.8-4.el8.x86_64 |
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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 |
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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'` |
To prevent unauthorized mail relay, configure Postfix to require authentication even for outgoing mail, 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 name> ●Add your domain name around line 103 #mydomain = domain.tld mydomain = <Domain name> ●Uncomment out per line 118 myorigin = $mydomain ●Change per line 135 inet_interfaces = all ●Added around line 183 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 # SSMTP-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 |
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# systemctl restart --now postfix |
2.Dovecot Install
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# dnf -y install dovecot |
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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 |
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# vi /etc/dovecot/conf.d/10-mail.conf ●Line 31 : Add mail_location = maildir:~/Maildir |
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# vi /etc/dovecot/conf.d/10-master.conf ●Line 107-109 : Uncommented and added # Postfix smtp-auth unix_listener /var/spool/postfix/private/auth { mode = 0666 user = postfix group = postfix } |
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# vi /etc/dovecot/conf.d/10-ssl.conf ●Per line 8 : Change ssl = yes |
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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 |
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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 mailx # echo 'export MAIL=$HOME/Maildir' >> /etc/profile.d/mail.sh Add user [linux] # useradd linux # passwd linux Set password for user linux New password: Retype new password: passwd: all authentication tokens updated successfully. |
①Log in as an email user and send a test email.
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# su - linux $ mail linux@localhost Subject: Test Mail mail test . ← To end the text, type ". " Enter EOT $ mail Heirloom Mail version 12.5 7/5/10. Type ? for help. "/home/linux/Maildir": 1 message 1 new >N 1 linux@korodes.com Fri Jul 15 22:26 17/510 "Test Mail" & 1 Message 1: From linux@korodes.com Fri Jul 15 22:26:39 2022 Return-Path: <linux@korodes.com> X-Original-To: linux@localhost Delivered-To: linux@localhost Date: Fri, 15 Jul 2022 22:26:39 +0900 To: linux@localhost Subject: Test Mail User-Agent: Heirloom mailx 12.5 7/5/10 Content-Type: text/plain; charset=us-ascii From: linux@korodes.com Status: Rmail test& |
Set up and confirm your account in Mozilla Thunderbird
①Start Thunderbird, and click "Tools", "Account Settings".
②「Account Actions」「Add Mail Account」
③Set as follows
Your full name : Any name
Email addtess : huong@korodes.com
Password : Password for user huong
Click on "Configure manually"
④Set "INCOMMING SERVER" and "OUTGOING SERVER" as shown below and click "Re-test".
⑤[The following settings were found by probinfg the given server] is displayed
After clicking "Done," the following "Warning" appears, but there is no problem, so click "Confirm.
⑥Click "Finish" when "Account syccessfuly created" is displayed.
Mail Server : Postfix + Clamav + Amavisd+SpamAssassin
1.Real-time scanning of e-mails
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# dnf --enablerepo=epel,powertools -y install amavisd-new clamd perl-Digest-SHA1 perl-IO-stringy |
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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 |
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# vi /etc/amavisd/amavisd.conf ●Per line 13 : Delete # at the beginning of the line @bypass_spam_checks_maps = (1); # controls running of anti-spam code ● Line 23: Change to your domain name $mydomain = 'Domain Name'; ●Per line 28 : comment-out #$QUARANTINEDIR = undef; # -Q ●Per line 125 : comment-out # $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 |
X-Virus-Scanned: amavisd-new at korodes.
![](https://korodes.com/wp-content/uploads/2022/05/151020d10b343e50d1e28236f23fa87b.png)
2.Email spam protection
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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. |
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# vi /etc/mail/spamassassin/v310.pre ●Per line 24 : Remove # at the beginning of the line loadplugin Mail::SpamAssassin::Plugin::DCC |
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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 # SpamAssassin再起動 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 |
SpamAssassin configuration file is created as of the current date.
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# ls -l /etc/mail/spamassassin total 1512 drwxr-xr-x 2 root root 40 Jul 15 22:38 channel.d -rw-r--r-- 1 root root 985 Apr 19 07:39 init.pre -rw-r--r-- 1 root root 499337 Jul 15 22:55 local.cf drwx------ 2 root root 6 Apr 19 07:39 sa-update-keys -rw-r--r-- 1 root root 62 Apr 19 07:39 spamassassin-default.rc -rwxr-xr-x 1 root root 35 Apr 19 07:39 spamassassin-helper.sh -rw-r--r-- 1 root root 55 Apr 19 07:39 spamassassin-spamc.rc -rw-r--r-- 1 root root 499289 Dec 29 2021 user_prefs -rw-r--r-- 1 root root 499289 Jul 15 22:55 user_prefs.org -rw-r--r-- 1 root root 2523 Jul 15 22:53 v310.pre -rw-r--r-- 1 root root 1194 Apr 19 07:39 v312.pre -rw-r--r-- 1 root root 2416 Apr 19 07:39 v320.pre -rw-r--r-- 1 root root 1237 Apr 19 07:39 v330.pre -rw-r--r-- 1 root root 1020 Apr 19 07:39 v340.pre -rw-r--r-- 1 root root 1114 Apr 19 07:39 v341.pre -rw-r--r-- 1 root root 1313 Apr 19 07:39 v342.pre -rw-r--r-- 1 root root 1264 Apr 19 07:39 v343.pre |
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# crontab -e 0 2 * * * /var/www/system/spamassassin-update.sh > /dev/null 2>&1 |
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# vi /etc/postfix/master.cf ●Per line 12. Add "#" to the beginning of the line and add SpamAssassin setting to line 13 # 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 |
![](https://korodes.com/wp-content/uploads/2022/05/6db91b7d45a56fa3651554b99716ffb3.png)