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| author | David Luevano Alvarado <david@luevano.xyz> | 2021-03-20 02:46:53 -0700 |
|---|---|---|
| committer | David Luevano Alvarado <david@luevano.xyz> | 2021-03-20 02:46:53 -0700 |
| commit | e331c60377e62f158bdcdedfc7a0664104cd8e03 (patch) | |
| tree | 9cdaa6fbafc6b4718108c0b6ca6fd37b6b46b4b2 /blog/dst/a/mail_server_with_postfix.html | |
| parent | 32d1f58c22c2de68c1ec7d8696777990c89c6e77 (diff) | |
Publish mail entry and reflect sbg fix
Diffstat (limited to 'blog/dst/a/mail_server_with_postfix.html')
| -rw-r--r-- | blog/dst/a/mail_server_with_postfix.html | 576 |
1 files changed, 576 insertions, 0 deletions
diff --git a/blog/dst/a/mail_server_with_postfix.html b/blog/dst/a/mail_server_with_postfix.html new file mode 100644 index 0000000..eafb6bf --- /dev/null +++ b/blog/dst/a/mail_server_with_postfix.html @@ -0,0 +1,576 @@ +<!DOCTYPE html> +<html lang="en"> + <head> + <script type="text/javascript" src="https://static.luevano.xyz/scripts/theme.js"></script> + + <link id="code-theme-css" rel="stylesheet" type="text/css" href="https://static.luevano.xyz/hl/styles/solarized-dark.min.css"> + <script type="text/javascript" src="https://static.luevano.xyz/hl/highlight.min.js"></script> + <script type="text/javascript">hljs.initHighlightingOnLoad();</script> + <link rel="stylesheet" type="text/css" href="https://static.luevano.xyz/fa/css/all.min.css"> + <link id="theme-css" rel="stylesheet" type="text/css" href="https://static.luevano.xyz/css/dark.css"> + <link rel="stylesheet" type="text/css" href="https://static.luevano.xyz/css/general_style.css"> + + <link rel="icon" href="https://static.luevano.xyz/fa/svgs/solid/dragon.svg"> + <meta charset="utf-8"> + + <title>LuĂ©vano's Blog</title> + </head> + + <body> + <div id="theme-switcher-container"> + <i class="fas fa-sun"></i> + <label class="switch theme"> + <input id="theme-switch" type="checkbox" onclick="toggleTheme()"> + <span class="slider round"></span> + </label> + <i class="fas fa-moon"></i> + </div> + + <header> + <ul class="menubar"> + <li> + <a href="https://luevano.xyz/"><i class="fas fa-home" alt="Home"></i><span>Home</span></a> + </li> + + <li> + <a href="https://blog.luevano.xyz/"><i class="fas fa-book-open" alt="Blog"></i><span>Blog</span></a> + </li> + + <li><i class="fab fa-git" alt="Git"></i><span>Git</span> + <ul> + <li><a href="https://git.luevano.xyz/" target="_blank"><i class="fab fa-git-alt" alt="Git-alt"></i></a></li> + + <li><a href="https://github.com/luevano" target="_blank"><i class="fab fa-github" alt="Github"></i></a></li> + + <li><a href="https://gitlab.com/dluevano" target="_blank"><i class="fab fa-gitlab" alt="Gitlab"></i></a></li> + </ul> + </li> + + <li><i class="fas fa-box-open" alt="Stuff"></i><span>Stuff</span> + <ul> + <li><a href="https://gb.luevano.xyz/"><i class="fas fa-gamepad" alt="Gameboy"></i><span>Gameboy</span></a></li> + </ul> + </li> + + <li> + <a href="https://luevano.xyz/donate"><i class="fas fa-donate" alt="Donate"></i><span>Donate</span></a> + <ul> + <li><a href="https://paypal.me/dlvna"><i class="fab fa-paypal" alt="Paypal"></i><span>Paypal</span></a></li> + </ul> + </li> + </ul> + </nav> + </header> +<h1>Create a Mail server with Postfix, Dovecot, SpamAssassin and OpenDKIM</h1> + +<p>The entry is going to be long because it's a <em>tedious</em> process. This is also based on <a href="https://github.com/LukeSmithxyz/emailwiz">Luke Smith's script</a>, but adapted to Arch Linux (his script works on debian-based distributions). This entry is mostly so I can record all the notes required while I'm in the process of installing/configuring the mail server on a new VPS of mine; also I'm going to be writing a script that does everything in one go (for Arch Linux), that will be hosted <a href="https://git.luevano.xyz/server_scripts.git">here</a>.</p> + +<p>This configuration works for local users (users that appear in <code>/etc/passwd</code>), and does not use any type of SQL. And note that most if not all commands executed here are run with root privileges.</p> + +<p>More in depth configuration is detailed in the Arch Wiki for each package used here.</p> + +<h2>Prerequisites</h2> + +<p>Basically the same as with the <a href="https://blog.luevano.xyz/a/website_with_nginx.html">website with Nginx and Certbot</a>:</p> + +<ul> +<li>A domain name. Got mine on <a href="https://www.epik.com/?affid=da5ne9ru4">Epik</a> (affiliate link, btw). + +<ul> +<li>Later we'll be adding some <strong>MX</strong> and <strong>TXT</strong> records.</li> +<li>You also need a <strong>CNAME</strong> for “mail” and (optionally) “www.mail”, or whatever you want to call the sub-domains (although the <a href="https://tools.ietf.org/html/rfc2181#section-10.3">RFC 2181</a> states that it NEEDS to be an <strong>A</strong> record, fuck the police), to actually work and to get SSL certificate (you can also use the SSL certificate obtained if you created a website following my other notes on <code>nginx</code> and <code>certbot</code>).</li> +</ul></li> +<li>A VPS or somewhere else to host. I'm using <a href="https://www.vultr.com/?ref=8732849">Vultr</a> (also an affiliate link). + +<ul> +<li>Also <code>ssh</code> configured.</li> +<li>Ports 25, 587 (SMTP), 465 (SMTPS), 143 (IMAP) and 993 (IMAPS) open on the firewall (I use <code>ufw</code>).</li> +<li>With <code>nginx</code> and <code>certbot</code> setup and running.</li> +</ul></li> +</ul> + +<h2>Postfix</h2> + +<p><a href="https://wiki.archlinux.org/index.php/Postfix">Postfix</a> is a “mail transfer agent” which is the component of the mail server that receives and sends emails via SMTP.</p> + +<p>Install the <code>postfix</code> package:</p> + +<pre><code class="language-sh">pacman -S postfix +</code></pre> + +<p>We have two main files to configure (inside <code>/etc/postfix</code>): <code>master.cf</code> (<a href="https://man.archlinux.org/man/master.5">master(5)</a>) and <code>main.cf</code> (<a href="https://man.archlinux.org/man/postconf.5">postconf(5)</a>). We're going to edit <code>main.cf</code> first either by using the command <code>postconf -e 'setting'</code> or by editing the file itself (I prefer to edit the file).</p> + +<p>Note that the default file itself has a lot of comments with description on what each thing does (or you can look up the manual, linked above), I used what Luke's script did plus some other settings that worked for me.</p> + +<p>Now, first locate where your website cert is, mine is at the default location <code>/etc/letsencrypt/live/</code>, so my <code>certdir</code> is <code>/etc/letsencrypt/live/luevano.xyz</code>. Given this information, change <code>{yourcertdir}</code> on the corresponding lines. The configuration described below has to be appended in the <code>main.cf</code> configuration file.</p> + +<p>Certificates and ciphers to use for authentication and security:</p> + +<pre><code class="language-conf">smtpd_tls_key_file = {yourcertdir}/privkey.pem +smtpd_tls_cert_file = {yourcertdir}/fullchain.pem +smtpd_use_tls = yes +smtpd_tls_auth_only = yes +smtp_tls_security_level = may +smtp_tls_loglevel = 1 +smtp_tls_CAfile = {yourcertdir}/cert.pem +smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1 +smtp_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1 +smtpd_tls_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1 +smtp_tls_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1 +tls_preempt_cipherlist = yes +smtpd_tls_exclude_ciphers = aNULL, LOW, EXP, MEDIUM, ADH, AECDH, MD5, + DSS, ECDSA, CAMELLIA128, 3DES, CAMELLIA256, + RSA+AES, eNULL + +smtp_tls_CApath = /etc/ssl/certs +smtpd_tls_CApath = /etc/ssl/certs + +smtpd_relay_restrictions = permit_sasl_authenticated, permit_mynetworks, defer_unauth_destination +</code></pre> + +<p>Also, for the <em>connection</em> with <code>dovecot</code>, append the next few lines (telling postfix that <code>dovecot</code> will use user/password for authentication):</p> + +<pre><code class="language-conf">smtpd_sasl_auth_enable = yes +smtpd_sasl_type = dovecot +smtpd_sasl_path = private/auth +smtpd_sasl_security_options = noanonymous, noplaintext +smtpd_sasl_tls_security_options = noanonymous +</code></pre> + +<p>Specify the mailbox home (this is going to be a directory inside your user's home):</p> + +<pre><code class="language-conf">home_mailbox = Mail/Inbox/ +</code></pre> + +<p>Pre-configuration to work seamlessly with <code>dovecot</code> and <code>opendkim</code>:</p> + +<pre><code class="language-conf">myhostname = {yourdomainname} +mydomain = localdomain +mydestination = $myhostname, localhost.$mydomain, localhost + +milter_default_action = accept +milter_protocol = 6 +smtpd_milters = inet:127.0.0.1:8891 +non_smtpd_milters = inet:127.0.0.1:8891 +mailbox_command = /usr/lib/dovecot/deliver +</code></pre> + +<p>Where <code>{yourdomainname}</code> is <code>luevano.xyz</code> in my case, or if you have <code>localhost</code> configured to your domain, then use <code>localhost</code> for <code>myhostname</code> (<code>myhostname = localhost</code>).</p> + +<p>Lastly, if you don't want the sender's IP and user agent (application used to send the mail), add the following line:</p> + +<pre><code class="language-conf">smtp_header_checks = regexp:/etc/postfix/smtp_header_checks +</code></pre> + +<p>And create the <code>/etc/postfix/smtp_header_checks</code> file with the following content:</p> + +<pre><code class="language-conf">/^Received: .*/ IGNORE +/^User-Agent: .*/ IGNORE +</code></pre> + +<p>That's it for <code>main.cf</code>, now we have to configure <code>master.cf</code>. This one is a bit more tricky.</p> + +<p>First look up lines (they're uncommented) <code>smtp inet n - n - - smtpd</code>, <code>smtp unix - - n - - smtp</code> and <code>-o syslog_name=postfix/$service_name</code> and either delete or uncomment them… or just run <code>sed -i "/^\s*-o/d;/^\s*submission/d;/\s*smtp/d" /etc/postfix/master.cf</code> as stated in Luke's script.</p> + +<p>Lastly, append the following lines to complete postfix setup and pre-configure for <code>spamassassin</code>.</p> + +<pre><code class="language-conf">smtp unix - - n - - smtp +smtp inet n - y - - smtpd + -o content_filter=spamassassin +submission inet n - y - - smtpd + -o syslog_name=postfix/submission + -o smtpd_tls_security_level=encrypt + -o smtpd_sasl_auth_enable=yes + -o smtpd_tls_auth_only=yes +smtps inet n - y - - smtpd + -o syslog_name=postfix/smtps + -o smtpd_tls_wrappermode=yes + -o smtpd_sasl_auth_enable=yes +spamassassin unix - n n - - pipe + user=spamd argv=/usr/bin/vendor_perl/spamc -f -e /usr/sbin/sendmail -oi -f \${sender} \${recipient} +</code></pre> + +<p>Now, I ran into some problems with postfix, one being <a href="https://www.faqforge.com/linux/fix-for-opensuse-error-postfixmaster-fatal-0-0-0-0smtps-servname-not-supported-for-ai_socktype/">smtps: Servname not supported for ai_socktype</a>, to fix it, as <em>Till</em> posted in that site, edit <code>/etc/services</code> and add:</p> + +<pre><code class="language-conf">smtps 465/tcp +smtps 465/udp +</code></pre> + +<p>Before starting the <code>postfix</code> service, you need to run <code>newaliases</code> first (but you can do a bit of configuration beforehand). Edit the file <code>/etc/postfix/aliases</code> and edit accordingly. I only change the <code>root: you</code> line (where <code>you</code> is the account that will be receiving “root” mail). Check the Arch Wiki for more info and other alternatives/options. After you're done, run:</p> + +<pre><code class="language-sh">postalias /etc/postfix/aliases +newaliases +</code></pre> + +<p>At this point you're done configuring <code>postfix</code> and you can already start/enable the <code>postfix</code> service:</p> + +<pre><code class="language-sh">systemctl start postfix.service +systemctl enable postfix.service +</code></pre> + +<h2>Dovecot</h2> + +<p><a href="https://wiki.archlinux.org/index.php/Dovecot">Dovecot</a> is an IMAP and POP3 server, which is what lets an email application retrieve the mail.</p> + +<p>Install the <code>dovecot</code> and <code>pigeonhole</code> (sieve for <code>dovecot</code>) packages:</p> + +<pre><code class="language-sh">pacman -S dovecot pigeonhole +</code></pre> + +<p>On arch, by default, there is no <code>/etc/dovecot</code> directory with default configurations set in place, but the package does provide the example configuration files. Create the <code>dovecot</code> directory under <code>/etc</code> and, optionally, copy the <code>dovecot.conf</code> file and <code>conf.d</code> directory under the just created <code>dovecot</code> directory:</p> + +<pre><code class="language-sh">mkdir /etc/dovecot +cp /usr/share/doc/dovecot/example-config/dovecot.conf /etc/dovecot/dovecot.conf +cp -r /usr/share/doc/dovecot/example-config/conf.d /etc/dovecot +</code></pre> + +<p>As Luke stated, <code>dovecot</code> comes with a lot of “modules” (under <code>/etc/dovecot/conf.d/</code> if you copied that folder) for all sorts of configurations that you can include, but I do as he does and just edits/creates the whole <code>dovecot.conf</code> file; although, I would like to check each of the separate configuration files <code>dovecot</code> provides I think the options Luke provides are more than good enough.</p> + +<p>I'm working with an empty <code>dovecot.conf</code> file. Add the following lines for SSL and login configuration (also replace <code>{yourcertdir}</code> with the same certificate directory described in the Postfix section above, note that the <code><</code> is required):</p> + +<pre><code class="language-conf">ssl = required +ssl_cert = <{yourcertdir}/fullchain.pem +ssl_key = <{yourcertdir}/privkey.pem +ssl_min_protocol = TLSv1.2 +ssl_cipher_list = ALL:!RSA:!CAMELLIA:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!SRP:!DSS:!RC4:!SHA1:!SHA256:!SHA384:!LOW@STRENGTH +ssl_prefer_server_ciphers = yes +ssl_dh = </etc/dovecot/dh.pem + +auth_mechanisms = plain login +auth_username_format = %n +protocols = $protocols imap +</code></pre> + +<p>You may notice we specify a file we don't have under <code>/etc/dovecot</code>: <code>dh.pem</code>. We need to create it with <code>openssl</code> (you should already have it installed if you've been following this entry and the one for <code>nginx</code>). Just run (might take a few minutes):</p> + +<pre><code class="language-sh">openssl dhparam -out /etc/dovecot/dh.pem 4096 +</code></pre> + +<p>After that, the next lines define what a “valid user is” (really just sets the database for users and passwords to be the local users with their password):</p> + +<pre><code class="language-conf">userdb { + driver = passwd +} + +passdb { + driver = pam +} +</code></pre> + +<p>Next, comes the mail directory structure (has to match the one described in the Postfix section). Here, the <code>LAYOUT</code> option is important so the boxes are <code>.Sent</code> instead of <code>Sent</code>. Add the next lines (plus any you like):</p> + +<pre><code class="language-conf">mail_location = maildir:~/Mail:INBOX=~/Mail/Inbox:LAYOUT=fs +namespace inbox { + inbox = yes + + mailbox Drafts { + special_use = \Drafts + auto = subscribe + } + + mailbox Junk { + special_use = \Junk + auto = subscribe + autoexpunge = 30d + } + + mailbox Sent { + special_use = \Sent + auto = subscribe + } + + mailbox Trash { + special_use = \Trash + } + + mailbox Archive { + special_use = \Archive + } +} +</code></pre> + +<p>Also include this so Postfix can use Dovecot's authentication system:</p> + +<pre><code class="language-conf">service auth { + unix_listener /var/spool/postfix/private/auth { + mode = 0660 + user = postfix + group = postfix + } +} +</code></pre> + +<p>Lastly (for <code>dovecot</code> at least), the plugin configuration for <code>sieve</code> (<code>pigeonhole</code>):</p> + +<pre><code class="language-conf">protocol lda { + mail_plugins = $mail_plugins sieve +} + +protocol lmtp { + mail_plugins = $mail_plugins sieve +} + +plugin { + sieve = ~/.dovecot.sieve + sieve_default = /var/lib/dovecot/sieve/default.sieve + sieve_dir = ~/.sieve + sieve_global_dir = /var/lib/dovecot/sieve/ +</code></pre> + +<p>Where <code>/var/lib/dovecot/sieve/default.sieve</code> doesn't exist yet. Create the folders:</p> + +<pre><code class="language-sh">mkdir -p /var/lib/dovecot/sieve +</code></pre> + +<p>And create the file <code>default.sieve</code> inside that just created folder with the content:</p> + +<pre><code class="language-conf">require ["fileinto", "mailbox"]; +if header :contains "X-Spam-Flag" "YES" { + fileinto "Junk"; +} +</code></pre> + +<p>Now, if you don't have a <code>vmail</code> (virtual mail) user, create one and change the ownership of the <code>/var/lib/dovecot</code> directory to this user:</p> + +<pre><code class="language-sh">grep -q "^vmail:" /etc/passwd || useradd -m vmail -s /usr/bin/nologin +chown -R vmail:vmail /var/lib/dovecot +</code></pre> + +<p>Note that I also changed the shell for <code>vmail</code> to be <code>/usr/bin/nologin</code>. After that, run:</p> + +<pre><code class="language-sh">sievec /var/lib/dovecot/sieve/default.sieve +</code></pre> + +<p>To compile the configuration file (a <code>default.svbin</code> file will be created next to <code>default.sieve</code>).</p> + +<p>Next, add the following lines to <code>/etc/pam.d/dovecot</code> if not already present (shouldn't be there if you've been following these notes):</p> + +<pre><code class="language-conf">auth required pam_unix.so nullok +account required pam_unix.so +</code></pre> + +<p>That's it for <code>dovecot</code>, at this point you can start/enable the <code>dovecot</code> service:</p> + +<pre><code class="language-sh">systemctl start dovecot.service +systemctl enable dovecot.service +</code></pre> + +<h1>OpenDKIM</h1> + +<p><a href="https://wiki.archlinux.org/index.php/OpenDKIM">OpenDKIM</a> is needed so services like G**gle (we don't mention that name here [[[this is a meme]]]) don't throw the mail to the trash. DKIM stands for “DomainKeys Identified Mail”.</p> + +<p>Install the <code>opendkim</code> package:</p> + +<pre><code class="language-sh">pacman -S opendkim +</code></pre> + +<p>Generate the keys for your domain:</p> + +<pre><code class="language-sh">opendkim-genkey -D /etc/opendkim -d {yourdomain} -s {yoursubdomain} -r -b 2048 +</code></pre> + +<p>Where you need to change <code>{yourdomain}</code> and <code>{yoursubdomain}</code> (doesn't really need to be the sub-domain, could be anything that describes your key) accordingly, for me it's <code>luevano.xyz</code> and <code>mail</code>, respectively. After that, we need to create some files inside the <code>/etc/opendkim</code> directory. First, create the file <code>KeyTable</code> with the content:</p> + +<pre><code class="language-conf">{yoursubdomain}._domainkey.{yourdomain} {yourdomain}:{yoursubdomain}:/etc/opendkim/{yoursubdomain}.private +</code></pre> + +<p>So, for me it would be:</p> + +<pre><code class="language-conf">mail._domainkey.luevano.xyz luevano.xyz:mail:/etc/opendkim/mail.private +</code></pre> + +<p>Next, create the file <code>SigningTable</code> with the content:</p> + +<pre><code class="language-conf">*@{yourdomain} {yoursubdomain}._domainkey.{yourdomain} +</code></pre> + +<p>Again, for me it would be:</p> + +<pre><code class="language-conf">*@luevano.xyz mail._domainkey.luevano.xyz +</code></pre> + +<p>And, lastly create the file <code>TrustedHosts</code> with the content:</p> + +<pre><code class="language-conf">127.0.0.1 +::1 +10.1.0.0/16 +1.2.3.4/24 +localhost +{yourserverip} +... +</code></pre> + +<p>And more, make sure to include your server IP and something like <code>subdomain.domainname</code>.</p> + +<p>Next, edit <code>/etc/opendkim/opendkim.conf</code> to reflect the changes (or rather, additions) of these files, as well as some other configuration. You can look up the example configuration file located at <code>/usr/share/doc/opendkim/opendkim.conf.sample</code>, but I'm creating a blank one with the contents:</p> + +<pre><code class="language-conf">Domain {yourdomain} +Selector {yoursubdomain} + +Syslog Yes +UserID opendkim + +KeyFile /etc/opendkim/{yoursubdomain}.private +Socket inet:8891@localhost +</code></pre> + +<p>Now, change the permissions for all the files inside <code>/etc/opendkim</code>:</p> + +<pre><code class="language-conf">chown -R root:opendkim /etc/opendkim +chmod g+r /etc/postfix/dkim/* +</code></pre> + +<p>I'm using <code>root:opendkim</code> so <code>opendkim</code> doesn't complain about the <code>{yoursubdomani}.private</code> being insecure (you can change that by using the option <code>RequireSafeKeys False</code> in the <code>opendkim.conf</code> file, as stated <a href="http://lists.opendkim.org/archive/opendkim/users/2014/12/3331.html">here</a>).</p> + +<p>That's it for the general configuration, but you could go more in depth and be more secure with some extra configuration as described in the <a href="https://wiki.archlinux.org/index.php/OpenDKIM#Security">Arch Wiki entry for OpenDKIM</a>.</p> + +<p>Now, just start/enable the <code>opendkim</code> service:</p> + +<pre><code class="language-sh">systemctl start opendkim.service +systemctl enable opendkim.service +</code></pre> + +<p>And don't forget to add the following <strong>TXT</strong> records on your domain registrar (these examples are for Epik):</p> + +<ol start="1"> +<li><em>DKIM</em> entry: look up your <code>{yoursubdomain}.txt</code> file, it should look something like:</li> +</ol> + +<pre><code class="language-txt">{yoursubdomain}._domainkey IN TXT ( "v=DKIM1; k=rsa; s=email; " + "p=..." + "..." ) ; ----- DKIM key mail for {yourdomain} +</code></pre> + +<p>In the TXT record you will place <code>{yoursubdomain}._domainkey</code> as the “Host” and <code>"v=DKIM1; k=rsa; s=email; " "p=..." "..."</code> in the “TXT Value” (replace the dots with the actual value you see in your file).</p> + +<ol start="2"> +<li><p><em>DMARC</em> entry: just <code>_dmarc.{yourdomain}</code> as the “Host” and <code>"v=DMARC1; p=reject; rua=mailto:dmarc@{yourdomain}; fo=1"</code> as the “TXT Value”.</p></li> +<li><p><em>SPF</em> entry: just <code>@</code> as the “Host” and <code>"v=spf1 mx a:{yoursubdomain}.{yourdomain} - all"</code> as the “TXT Value”.</p></li> +</ol> + +<p>And at this point you could test your mail for spoofing and more, but you don't know -yet- how to login (it's really easy, but I'm gonna state that at the end of this entry).</p> + +<h2>SpamAssassin</h2> + +<p><a href="https://wiki.archlinux.org/index.php/SpamAssassin">SpamAssassin</a> is just <em>a mail filter to identify spam</em>.</p> + +<p>Install the <code>spamassassin</code> package (which will install a bunch of ugly <code>perl</code> packages…):</p> + +<pre><code class="language-sh">pacman -S spamassassin +</code></pre> + +<p>For some reason, the permissions on all <code>spamassassin</code> stuff are all over the place. First, change owner of the executables, and directories:</p> + +<pre><code class="language-sh">chown spamd:spamd /usr/bin/vendor_perl/sa-* +chown spamd:spamd /usr/bin/vendor_perl/spam* +chwown -R spamd:spamd /etc/mail/spamassassin +</code></pre> + +<p>Then, you can edit <code>local.cf</code> (located in <code>/etc/mail/spamassassin</code>) to fit your needs (I only uncommented the <code>rewrite_header Subject ...</code> line). And then you can run the following command to update the patterns and compile them:</p> + +<pre><code class="language-sh">sudo -u spamd sa-update +sudo -u spamd sa-compile +</code></pre> + +<p>And since this should be run periodically, create the service <code>spamassassin-update.service</code> under <code>/etc/systemd/system</code> with the following content:</p> + +<pre><code class="language-conf">[Unit] +Description=SpamAssassin housekeeping +After=network.target + +[Service] +User=spamd +Group=spamd +Type=oneshot + +ExecStart=/usr/bin/vendor_perl/sa-update --allowplugins +SuccessExitStatus=1 +ExecStart=/usr/bin/vendor_perl/sa-compile +ExecStart=/usr/bin/systemctl -q --no-block try-restart spamassassin.service +</code></pre> + +<p>And you could also execute <code>sa-learn</code> to train <code>spamassassin</code>'s bayes filter, but this works for me. Then create the timer <code>spamassassin-update.timer</code> under the same directory, with the content:</p> + +<pre><code class="language-conf">[Unit] +Description=SpamAssassin housekeeping + +[Timer] +OnCalendar=daily +Persistent=true + +[Install] +WantedBy=timers.target +</code></pre> + +<p>You can now start/enable the <code>spamassassin-update</code> timer:</p> + +<pre><code class="language-sh">systemctl start spamassassin-update.timer +systemctl enable spamassassin-update.timer +</code></pre> + +<p>Next, you may want to edit the <code>spamassassin</code> service before starting and enabling it, because by default, it could <a href="https://rimuhosting.com/howto/memory.jsp">spawn a lot of “childs”</a> eating a lot of resources and you really only need one child. Append <code>--max-children=1</code> to the line <code>ExecStart=...</code> in <code>/usr/bin/systemd/system/spamassassin.service</code>:</p> + +<pre><code class="language-conf">... +ExecStart=/usr/bin/vendor_perl/spamd -x -u spamd -g spamd --listen=/run/spamd/spamd.sock --listen=localhost --max-children=1 +... +</code></pre> + +<p>Finally, start and enable the <code>spamassassin</code> service:</p> + +<pre><code class="language-sh">systemctl start spamassassin.service +systemctl enable spamassassin.service +</code></pre> + +<h2>Wrapping up</h2> + +<p>We should have a working mail server by now. Before continuing check your journal logs (<code>journalctl -xe --unit={unit}</code>, where <code>{unit}</code> could be <code>spamassassin.service</code>for example) to see if there was any error whatsoever and try to debug it, it should be a typo somewhere (the logs are generally really descriptive) because all the settings and steps detailed here just (literally just finished doing everything on a new server as of the writing of this text) worked <em>(((it just werks on my machine)))</em>.</p> + +<p>Now, to actually use the mail service: first of all, you need a <em>normal</em> account (don't use root) that belongs to the <code>mail</code> group (<code>gpasswd -a user group</code> to add a user <code>user</code> to group <code>group</code>) and that has a password.</p> + +<p>Next, to actually login into a mail app/program/whateveryouwanttocallit, you will use the following settings, at least for <code>thunderdbird</code>(I tested in windows default mail app and you don't need a lot of settings):</p> + +<ul> +<li>* server: subdomain.domain (mail.luevano.xyz in my case)</li> +<li><strong>SMTP</strong> port: 587</li> +<li><strong>SMTPS</strong> port: 465 (I use this one)</li> +<li><strong>IMAP</strong> port: 143</li> +<li><strong>IMAPS</strong> port: 993 (again, I use this one)</li> +<li>Connection/security: SSL/TLS</li> +<li>Authentication method: Normal password</li> +<li>Username: just your <code>user</code>, not the whole email (<code>david</code> in my case)</li> +<li>Password: your <code>user</code> password (as in the password you use to login to the server with that user)</li> +</ul> + +<p>All that's left to do is test your mail server for spoofing, and to see if everything is setup correctly. Go to <a href="https://www.appmaildev.com/en/dkim">DKIM Test</a> and follow the instructions (basically click next, and send an email with whatever content to the email that they provide). After you send the email, you should see something like:</p> + +<p><img src="https://static.luevano.xyz/images/b/notes/mail/dkim_test_successful.png" alt="DKIM Test successful" /></p> + +<p>(Yes, I blurred a lot in the picture just to be sure, either way what's important is the list on the bottom part of the image)</p> + +<p>Finally, that's actually it for this entry, if you have any problem whatsoever you have my info down below.</p> + +<div class=timestamp> +<hr> +<p>Created: Sat, Mar 20, 2021 @ 02:23 MST</p> +</div> + <footer class="footer"> + <i class="fas fa-envelope" alt="Email"></i> + Email + <a href="mailto:david@luevano.xyz"> + david@luevano.xyz + </a> + <br> + + <i class="fas fa-rss" alt="RSS"></i> + RSS + <a href="https://blog.luevano.xyz/rss.xml"> + https://blog.luevano.xyz/rss.xml + </a> + <br> + + <i class="fas fa-donate" alt="Donate"></i> + <a href="https://luevano.xyz/donate">Donate</a> + <a href="https://paypal.me/dlvna"><i class="fab fa-paypal" alt="Paypal"></i></a> + </footer> + </body> +</html> |