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Table of Contents
Making Slackware Mail Server
This article shows how to make an Slackware machine your personal Mail Server. This howto is for Slackware 64 13.37, but with few changes you can adapt it to the newest member of the Slackware family.
Before beginning, you need a normal installation of Slackware, without any special packages. You will manually download and install from Slackbuilds.org extra packages needed to make a Mail Server. This article uses Cyrus SASL authentication and Cyrus IMAP for remote login, rather than alternatives like qpopper or dovecot.
You will install Cyrus-SASL, Postfix, Cyurs-IMAP, and then configure them to use certificates for encrypting the mail packages that traverse the Internet.
Installing Cyrus-SASL
# cd /tmp # mkdir cyrus-sasl # cd cyrus-sasl # wget ftp://ftp.slackware.com/pub/slackware/slackware64-13.37/source/n/cyrus-sasl/cyrus-sasl-2.1.23.tar.xz # wget ftp://ftp.slackware.com/pub/slackware/slackware64-13.37/source/n/cyrus-sasl/cyrus-sasl.SlackBuild # wget ftp://ftp.slackware.com/pub/slackware/slackware64-13.37/source/n/cyrus-sasl/doinst.sh.gz # wget ftp://ftp.slackware.com/pub/slackware/slackware64-13.37/source/n/cyrus-sasl/rc.saslauthd.gz # wget ftp://ftp.slackware.com/pub/slackware/slackware64-13.37/source/n/cyrus-sasl/slack-desc
# joe cyrus-sasl.SlackBuild
and add the following lines after “–disable static”
--enable-plain \ --disable-digest \
# sh cyrus-sasl.SlackBuild # installpkg /tmp/cyrus-sasl-2.1.23-x86_64-1.txz
Installing Postfix
# cd /tmp # mkdir postfix # cd postfix # wget http://postfix.cs.utah.edu/source/official/postfix-2.8.3.tar.gz # wget http://slackbuilds.org/slackbuilds/13.37/network/postfix/README # wget http://slackbuilds.org/slackbuilds/13.37/network/postfix/doinst.sh # wget http://slackbuilds.org/slackbuilds/13.37/network/postfix/postfix.SlackBuild # wget http://slackbuilds.org/slackbuilds/13.37/network/postfix/postfix.info # wget http://slackbuilds.org/slackbuilds/13.37/network/postfix/rc.postfix # wget http://slackbuilds.org/slackbuilds/13.37/network/postfix/slack-desc
# joe postfix.Slackbuild
Edit the following line and replace “dovecot” with “cyrus” like this:
SASL=${SASL:-cyrus}
To begin Postfix installation, you must create the postfix user and group. Later, you will add the user postfix and user cyrus to the mail group.
# groupadd -g 200 postfix # useradd -u 200 -d /dev/null -s /bin/false -g postfix postfix -G mail # groupadd -g 201 postdrop # sh postfix.SlackBuild # installpkg /tmp/postfix-2.8.3-x86_64-1_SBo.tgz
Before continuing, configure Postfix can authenticate with sasl. First, make some aliases and tell Postfix to use aliases maps from /etc/postfix/aliases:
# joe /etc/postfix/main.cf
Edit these lines and make them look like this:
alias_maps = hash:/etc/postfix/aliases alias_database = hash:/etc/postfix/aliases
Now add a user to your Slackware machine, a user who will also can read and send mail.
# adduser Login name for new user []: slackware_user User ID ('UID') [ defaults to next available ]: press ENTER Initial group [ users ]: 200 Home directory [ /home/xxxxxx ]: press ENTER Shell [ /bin/bash ]: /bin/false Do you wish to change the sheel? (Y/n): n Expiry date (YYYY-MM-DD) []: press ENTER
Press ENTER and input full name and other account-related stuff. Also specify a password for your newly created user.
Now edit /etc/postfix/aliases and modify it to your needs :
root : slackware_user office: slackware_user
Update your aliases database:
# postalias hash:/etc/postfix/aliases
Make the required configuration changes to Postfix so it can run:
# joe /etc/postfix/main.cf myhostname = mx.yourdomain.tld mydomain = yourdomain.tld myorigin = $mydomain inet_interfaces = all mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain mynetworks = 127.0.0.0/8
Configure Postfix to authenticate users using SASL:
# mkdir /etc/sasl2 # cd /etc/sasl2 # touch smtpd.conf # joe smtpd.conf
pwcheck_method: saslauthd mech_list: PLAIN LOGIN
Next, configure Postfix to have users authenticate using SASL. Edit /etc/postfix/main.cf and add the folowing code to the end of the file:
smtpd_sasl_auth_enable = yes broken_sasl_auth_clients = yes smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination
Start the daemons and test our configurations until now:
# saslauthd -a shadow # postfix start
Then from another machine, telnet into your mail server on port 25 and issue the following commands :
# telnet mx.mailserver.com 25 ehlo user.mailserver.tld 250-mx.mailserver.com 250-PIPELINING 250-SIZE 10240000 250-VRFY 250-ETRN 250-AUTH PLAIN LOGIN 250-AUTH=PLAIN LOGIN 250-ENHANCEDSTATUSCODES 250-8BITMIME 250 DSN AUTH PLAIN Y4R0QYxpcuHsFBRbbGjnPHIwYjB0MWrpMTk7La== 235 2.7.0 Authentication successful MAIL FROM: <user@mailserver.com> 250 2.1.0 Ok RCPT TO: <user@yahoo.com> 250 2.1.5 Ok DATA 354 End data with <CR><LF>.<CR><LF> HI. This mail is a test . . 250 2.0.0 Ok: queued as 4C0EE221E93 QUIT
printf 'user\0user\0password' | mmencode
on your mail server, where user is your username and password is your password
Installing Mail Delivery and Cyrus IMAP
# cd /tmp # mkdir cyrus-imap # cd cyrus-imap # wget http://cyrusimap.org/releases/cyrus-imapd-2.4.12.tar.gz # wget http://slackbuilds.org/slackbuilds/13.37/network/cyrus-imapd/README # wget http://slackbuilds.org/slackbuilds/13.37/network/cyrus-imapd/README.SLACKWARE # wget http://slackbuilds.org/slackbuilds/13.37/network/cyrus-imapd/cyrus-imapd.SlackBuild # wget http://slackbuilds.org/slackbuilds/13.37/network/cyrus-imapd/cyrus-imapd.info # wget http://slackbuilds.org/slackbuilds/13.37/network/cyrus-imapd/doinst.sh # wget http://slackbuilds.org/slackbuilds/13.37/network/cyrus-imapd/imapd.conf # wget http://slackbuilds.org/slackbuilds/13.37/network/cyrus-imapd/patches # wget http://slackbuilds.org/slackbuilds/13.37/network/cyrus-imapd/rc.cyrus-imapd # wget http://slackbuilds.org/slackbuilds/13.37/network/cyrus-imapd/slack-desc # mkdir patches # cd patches/ # wget http://mirrors.vbi.vt.edu/mirrors/linux/slackbuilds/13.37/network/cyrus-imapd/patches/cyrus-imapd-2.4.4-autocreate-0.10-0-sv1.patch # wget http://mirrors.vbi.vt.edu/mirrors/linux/slackbuilds/13.37/network/cyrus-imapd/patches/cyrus-imapd-2.4.4-autosieve-0.6.0-sv1.patch # cd /tmp/cyrus-imap # groupadd -g 238 cyrus # useradd -d /var/imap -s /bin/sh -u 238 -g 238 cyrus -G mail # sh cyrus-imapd.SlackBuild # installpkg /tmp/cyrus-imapd-2.4.12-x86_64-1_SBo.tgz # mkdir -m 750 -p /var/imap /var/spool/imap /var/sieve # chown cyrus:mail /var/imap /var/spool/imap /var/sieve # su - cyrus # /usr/doc/cyrus-imapd-2.4.12/tools/mkimap # su - root
Edit /etc/imapd.conf and add the following lines:
sasl_mech_list: PLAIN LOGIN allowplaintext: yes
Edit /etc/postfix/main.cf and at mailbox_transport add the following:
mailbox_transport = lmtp:unix:/var/imap/socket/lmtp
The last step to do is to add users to your imap server.
# passwd cyrus # cyradm --user cyrus --server localhost --auth plain localhost>cm user.slackware_user localhost>lm localhost> quit
At this point, you have a functional Mail Server, but with users authenticating in plain text . So the next step is inevitable.
SSL / TLS Postfix and Cyrus
Start by creating certificates and configuring POSTFIX to use STARTTLS.
# cd /etc/ssl # misc/CA.pl -newca ( complete all entries) # openssl req -new -nodes -keyout mailkey.pem -out mailreq.pem -days 36500 # openssl ca -out mail_signed_cert.pem -infiles mailreq.pem # cp /etc/ssl/mailkey.pem /etc/postfix # cp /etc/ssl/mail_signed_cert.pem /etc/postfix # chown root /etc/postfix/mailkey.pem # chmod 400 /etc/postfix/mailkey.pem # cp /etc/ssl/demoCA/cacert.pem /etc/postfix
Add the followings to /etc/postfix/main.cf :
smtpd_use_tls = yes smtpd_tls_key_file = /etc/postfix/mailkey.pem smtpd_tls_cert_file = /etc/postfix/mail_signed_cert.pem smtpd_tls_CAfile = /etc/postfix/cacert.pem
smtps inet n - n - - smtpd -o smtpd_tls_wrappermode=yes -o smtpd_sasl_auth_enable=yes
Now configure IMAP to use STARTTLS:
# openssl req -new -nodes -out req.pem -keyout key.pem # openssl rsa -in key.pem -out new.key.pem # openssl x509 -in req.pem -out ca-cert -req -signkey new.key.pem -days 36500 # cp new.key.pem /var/imap/server.pem # rm new.key.pem # cat ca-cert >> /var/imap/server.pem # chown cyrus:mail /var/imap/server.pem # chmod 600 /var/imap/server.pem # echo tls_ca_file: /var/imap/server.pem >> /etc/imapd.conf # echo tls_cert_file: /var/imap/server.pem >> /etc/imapd.conf # echo tls_key_file: /var/imap/server.pem >> /etc/imapd.conf
Adding daemons to rc.local
The final step is to add all daemons to rc.local so they can start when machine boots. Open /etc/rc.d/rc.local and add these lines :
# Starting saslauthd daemon if [ ! -r /var/state/saslauthd/saslauthd.pid ]; then echo "Starting SASL authentication daemon: /usr/sbin/saslauthd -a shadow" /usr/sbin/saslauthd -a shadow fi
# Starting IMAP daemon if [ -x /usr/libexec/cyrus/master ]; then echo "Starting Cyrus IMAP daemon: /usr/libexec/cyrus/master" /etc/rc.d/rc.cyrus-imapd start fi
# Starting POSTFIX daemon /etc/rc.d/rc.postfix start
Sources
Postfix The Definitive Guide, Kyle D. Dent, O'Reilly Managing IMAP, Dianna Mullet & Kevin Mullet, O'Reilly Official Postfix Documentation, [[http://www.postfix.org/documentation.html]]