• Start with the official installation docs using apt
• Then when that fails

• with install dbconfig-common to set up DB using mysql just doesn't work.
• it didn't work for mailman and it didn't work here
• it Says “password doesn't match requirements” (which isn't true).
• you have to set up the DB yourself

sudo mysql -p -e "CREATE DATABASE IF NOT EXISTS sympa CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci; CREATE USER IF NOT EXISTS 'sympa'@'localhost' IDENTIFIED BY '<RANDOM PASSWORD HERE>'; GRANT ALL PRIVILEGES ON sympa.* TO 'sympa'@'localhost'; FLUSH PRIVILEGES;"

sudo bash -c 'cat >> /etc/sympa/sympa/sympa.conf <<EOF
###\\\\ Database parameters ////###
db_type mysql
db_host localhost
db_user sympa
db_passwd <RANDOM PASSWORD HERE>
db_name sympa
EOF'

apparently standard setup is with Apache? But this works

server {
    listen 80;
    server_name <SUBDOMAIN NAME HERE>;
    return 301 https://$host$request_uri;
}

server {
    listen 443 ssl; 
    server_name <SUBDOMAIN NAME HERE>;

    ssl_certificate /etc/letsencrypt/live/<SOMETHINGSOMETHING>/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/<SOMETHINGSOMETHING>//privkey.pem;

    root /usr/lib/cgi-bin/sympa;
    
    access_log /var/log/nginx/sympa-access.log;
    error_log /var/log/nginx/sympa-error.log;

    location /static-sympa/ {
        alias /usr/share/sympa/static_content/;
        access_log off;
    }

    location /css-sympa/ {
        alias /var/lib/sympa/css/;
        access_log off;
    }

    location /pictures-sympa/ {
        alias /var/lib/sympa/pictures/;
        access_log off;
    }

    location / {
        include fastcgi_params;
        fastcgi_pass unix:/run/sympa/wwsympa.socket;
        fastcgi_param SCRIPT_FILENAME /usr/lib/cgi-bin/sympa/wwsympa.fcgi;
        fastcgi_param SCRIPT_NAME "";
        fastcgi_param PATH_INFO $uri;
    }
}

• Postfix tries to run some sympa stuff as an unprivileged user. Add this line to have it run as the sympa user instead:

sympa     unix  -       n       n      -        -       pipe
  flags=R user=sympa argv=/usr/lib/sympa/bin/queue ${recipient}

• add this to the mydestination line: <YOUR SUBDOMAIN>
• add hash:/etc/postfix/transport to the transport_maps line
• add hash:/etc/sympa/aliases.sympa.postfix to alias_maps
• add alias_database = hash:/etc/sympa/aliases.sympa.postfix
• suggestion (for sending larger emails): message_size_limit = 41943040

sympa     unix  -       n       n      -        -       pipe
  flags=R user=sympa argv=/usr/lib/sympa/bin/queue ${recipient}

wwsympa_url <YOUR_SUBDOMAIN>

# 1. Add email address text when list is created
alias_manager /usr/lib/sympa/bin/alias_manager.pl

# 2. compile email address text and add to db
aliases_program /usr/sbin/postalias

# 3. file Location for text and db
sendmail_aliases /etc/sympa/aliases.sympa.postfix

# If you have trouble change from default log_level 1
log_level 2

# The sympa manager defaults to sympa so emails to subscribe/unsubscribe etc. will come from sympa@DOMAIN. You can change this. For example, to have them come from manager instead add the below line:
email manager

• config is at /etc/sympa/sympa/sympa.conf
• when reading official documentation $SYSCONFDIR is /etc/sympa
• when reading official documentation $LIBEXECDIR is /usr/share/sympa/bin

• sympa logs go to syslog. View in realtime: sudo tail -f /var/log/syslog | grep --line-buffered -Ei 'sympa|wwsympa
• postfix logs go to /var/log/mail.log

• if forwarding emails to Amazon SES for sending, Amazon gets upset because of a duplicate header: Precedence
  • This is because Sympa adds a Precedence: bulk (or list) header automatically to all list traffic to help spam filters identify it as a mailing list.
  • Apparently the outgoing sender might have also added a Precedence header or maybe sympa is just confused
  • The result is that there is no Precedence header at all but that header has been obsoleted anyway so nothing lost
• to fix, add to /etc/sympa/sympa/sympa.conf: remove_outgoing_headers Precedence

Sympa uses a “Cascading” template system. It looks for a template (like welcome.tt2) in this specific order:

1. List Level: /var/lib/sympa/list_data/[list_name]/mail_tt2/ (Highest Priority)
2. Robot/Domain Level: /etc/sympa/[domain]/mail_tt2/
3. Site Level: /etc/sympa/mail_tt2/
4. Default: /usr/share/sympa/default/mail_tt2/ (Lowest Priority)

To customize a template for one specific list, copy the default file into that list's folder and edit it there.

• There's the “standard” list-unsubscribe header as defined in RFC 2369 and a newer “one-click” header as defined in RFC 8058
• Sympa v6.2.70 as packaged with ubuntu 24.04 generates the standard header automatically by default
• The newer “one-click” header is not supported until v6.2.72

• If the header is working properly there will be a line of hidden metadata at the top of an email that looks something like

List-Unsubscribe: <mailto:sympa@<DOMAIN>?subject=SIGNOFF%20<LIST_NAME>>, <https://<DOMAIN>/signoff/<LIST_NAME>/user@email.com>

• If this header is present, Gmail, Yahoo, and “friends” will automatically display their native “Unsubscribe” button next to the sender's name.

• config file located at: /var/lib/sympa/list_data/<LISTNAME>/config
• To get the emails sent from the list instead of the sender in the UI:
  • Admin → Edit List Config → DKIM/DMARC/ARC
    • DMARC Protection → All
    • New From name format → "Name" (via list)
• Change the from address from the sender to the list:
  • Admin → Edit List Config → Sending/Receiving Setup
  • "Reply address" → change to All
• Prepend the list name to the subjects when sending out:
  • Admin → Edit List Config → Sending/Receiving Setup
  • Subject tagging (custom_subject) → [% list.name %]

• the logo does not change the size of the blue line at the top of the site so you will get a logo that straddles blue and white
• with the nginx setup above the logo and favicon images should live at /usr/share/sympa/static_content
• to get sympa to see them edit/add these lines to /etc/sympa/sympa/sympa.conf:

logo_html_definition <a href="https://<DOMAIN>"><img src="/static-sympa/<FILENAME>" alt="my great logo" style="max-height: 120px; width: auto; border: 0;"></a>
# adjust max-height as appropriate
favicon_url /static-sympa/<BASEFILENAME>.ico

• It's a good idea to set the domain up with Google Postmaster Tools for some analytics sending to gmail addresses if you ever need it
• There's a list template which sets the defaults for new lists when they are created. It's possible to override with a new template. I did not look further into this.