Mainly as a note to self.

My default firewall setup

sudo ufw status
sudo ufw default allow outgoing
sudo ufw default deny incoming
grep IPV6 /etc/default/ufw
sudo ufw allow ssh
sudo ufw limit ssh/tcp comment 'Rate limit for openssh server'
sudo ufw allow 80/tcp comment 'Allow nginx HTTP'
sudo ufw limit 80 comment 'limit nginx HTTP'
sudo ufw allow 443/tcp comment 'Allow nginx HTTPS'
# For Domino mail
sudo ufw allow 1352/tcp comment 'Allow Notes replication'
sudo ufw allow 25/tcp comment 'Allow SMTP'
sudo ufw allow 587/tcp comment 'Allow SMTP'
sudo ufw allow 110/tcp comment 'Allow POP3'
sudo ufw allow 995/tcp comment 'Allow POP3s'
sudo ufw allow 143/tcp comment 'Allow IMAP'
sudo ufw allow 993/tcp comment 'Allow IMAPs'
sudo ufw allow from 1.2.3.4 'Allow the othe Domino'
sudo ufw enable