Contents
Clamav (anti-virus software)Install
1.Clam AntiVirus install
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# dnf -y install clamav clamd clamav-update |
2.Clam AntiVirus Configuration File Edit
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# vi /etc/clamd.d/scan.conf ●Line 14 # Default: disabled LogFile /var/log/clamd.scan ← ●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 |
4.Virus definition file update
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# freshclam ClamAV update process started at Tue Oct 25 13:58:31 2022 daily database available for download (remote version: 26698) Time: 1.0s, ETA: 0.0s [========================>] 57.31MiB/57.31MiB Testing database: '/var/lib/clamav/tmp.9c8fe0fc28/clamav-20801f5a7cee7ffecf89a9ee629d20da.tmp-daily.cvd' ... Database test passed. daily.cvd updated (version: 26698, sigs: 2008985, f-level: 90, builder: raynman) main database available for download (remote version: 62) Time: 2.1s, ETA: 0.0s [========================>] 162.58MiB/162.58MiB Testing database: '/var/lib/clamav/tmp.9c8fe0fc28/clamav-c0a11eb06c4b4ac1e742a7897f8e960f.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: 0.1s, ETA: 0.0s [========================>] 286.79KiB/286.79KiB Testing database: '/var/lib/clamav/tmp.9c8fe0fc28/clamav-18b7cfc85f2656ad1fabfe517c7a0b15.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 preset: disabled) Active: active (running) since Thu 2023-01-05 10:03:54 JST; 20s ago Docs: man:clamd(8) man:clamd.conf(5) https://www.clamav.net/documents/ Main PID: 10553 (clamd) Tasks: 2 (limit: 10883) Memory: 1.2G CPU: 20.559s CGroup: /system.slice/system-clamd.slice/clamd@scan.service mq10553 /usr/sbin/clamd -c /etc/clamd.d/scan.conf Jan 05 10:03:53 Alma clamd[10553]: ELF support enabled. Jan 05 10:03:53 Alma clamd[10553]: Mail files support enabled. Jan 05 10:03:53 Alma clamd[10553]: OLE2 support enabled. Jan 05 10:03:53 Alma clamd[10553]: PDF support enabled. Jan 05 10:03:53 Alma clamd[10553]: SWF support enabled. Jan 05 10:03:53 Alma clamd[10553]: HTML support enabled. Jan 05 10:03:53 Alma clamd[10553]: XMLDOCS support enabled. Jan 05 10:03:53 Alma clamd[10553]: HWP3 support enabled. Jan 05 10:03:53 Alma clamd[10553]: Self checking every 600 seconds. Jan 05 10:03:54 Alma systemd[1]: Started clamd scanner (scan) daemon. |
6.Conducted 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 /root/eicar.com: Removed. ----------- SCAN SUMMARY ----------- Known viruses: 8647067 Engine version: 0.103.7 Scanned directories: 1 Scanned files: 3 Infected files: 1 Data scanned: 0.00 MB Data read: 0.00 MB (ratio 0.00:1) Time: 62.724 sec (1 m 2 s) Start Date: 2023:01:05 10:05:28 End Date: 2023:01:05 10:06:31 |
7.Deployment of virus scan auto-execution scripts
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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. |
9.Scheduled virus scan execution
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# crontab -e 0 1 * * * /var/www/system/clamscan.sh > /dev/null 2>&1 |
Mail Server Install
1. Postfix
1.1 Install
Install Postfix and build an SMTP server
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# dnf -y install postfix |
Confirm 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.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 |
1.3Backup 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 per line 96 #myhostname = virtual.domain.tld myhostname = mail.<Domain> ●Add your domain name around line 103 #mydomain = domain.tld mydomain = <Domain> ●Delete comment 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 per 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 per line 447 #mail_spool_directory = /var/mail mail_spool_directory = /var/spool/mail ●Added per 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 |
Allow 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 restart --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 per 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 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 ●Line 107-109 : Uncommented and added # 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 it
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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 Allow POP/IMAP services in Firewalld Port Allow
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
①new user
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 Install # 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
①Log in as an email user and send a test email.
①Log 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 |
②Email Confirmation
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$ mail s-nail version v14.9.22. Type `?' for help /home/linux/Maildir: 1 message 1 new ?N 1 linux@korodes.com 2023-01-05 10:45 14/408 "Test Mail " & 1 [-- Message 1 -- 14 lines, 408 bytes --]: Date: Thu, 05 Jan 2023 10:45:32 +0900 To: linux@localhost Subject: Test Mail Message-Id: <20230105014532.B57C4226AF47@mail.korodes.com> From: linux@korodes.com mail test & |
3.4 operation check ②
Set up and confirm your account in Mozilla Thunderbird(For OS user huong as mail user)
①Start Thunderbird
Your full name : Any name
Email addtess : huong@korodes.com
Password : Password for huong
Enter each 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 Serever : Postfix + Clamav + Amavisd+SpamAssassin
1.Real-time scanning of e-mails
①Amavisd ,Clamav Server install
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# dnf config-manager --set-enabled crb # 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 |
⑤Confirmed by Thunderbird
I sent a test email to myself in Thunderbird, and the following appears in the header display of the received email
"X-Virus-Scanned: amavisd-new at korodes.com"
"X-Virus-Scanned: amavisd-new at korodes.com"
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 in the /etc/mail/spamassassin directory has been created with the current date.
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# ls -l /etc/mail/spamassassin total 1612 drwxr-xr-x 2 root root 40 Jan 5 11:04 channel.d -rw-r--r-- 1 root root 1194 Mar 31 2022 init.pre -rw-r--r-- 1 root root 499337 Jan 5 11:22 local.cf drwx------ 2 root root 6 Mar 31 2022 sa-update-keys -rw-r--r-- 1 root root 62 Mar 31 2022 spamassassin-default.rc -rwxr-xr-x 1 root root 39 Mar 31 2022 spamassassin-helper.sh -rw-r--r-- 1 root root 55 Mar 31 2022 spamassassin-spamc.rc -rw-r--r-- 1 root root 499289 Dec 29 2021 user_prefs -rw-r--r-- 1 root root 499289 Jan 5 11:22 user_prefs.org -rw-r--r-- 1 root root 2523 Jan 5 11:21 v310.pre -rw-r--r-- 1 root root 1194 Mar 31 2022 v312.pre -rw-r--r-- 1 root root 2416 Mar 31 2022 v320.pre -rw-r--r-- 1 root root 1237 Mar 31 2022 v330.pre -rw-r--r-- 1 root root 1020 Mar 31 2022 v340.pre -rw-r--r-- 1 root root 1309 Mar 31 2022 v341.pre -rw-r--r-- 1 root root 1469 Mar 31 2022 v342.pre -rw-r--r-- 1 root root 1264 Mar 31 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」
