Cannot send emails on a IPv6-only host

[olegbliaher]

🐛 Bug Report

🔬 How To Reproduce

Steps to reproduce the behavior:

1. Start console
2. TestMailer.send_test_email("[email protected]").deliver_now

Code sample

--> Configured FROM: address: '[email protected]'
--> Default port is 25 but will only be used if smtp_address is set.

The settings.yml mail configuration is:

raise_delivery_errors: true
smtp_port: 25
smtp_enable_starttls_auto: true
smtp_open_timeout: 10
smtp_read_timeout: 10
mailer_sender: [email protected]
smtp_starttls: true
smtp_password: [HIDDEN]
smtp_openssl_verify_mode: none
smtp_user_name: username
smtp_address: smtp.server.com

The Mail subsystem SMTP configuration is:

address: smtp.server.com
port: 25
open_timeout: 10
read_timeout: 10
user_name: user
password: [HIDDEN]
openssl_verify_mode: none
enable_starttls_auto: true

Environment

Where are you running/using Password Pusher?

• pwpush.com
• Docker Image
  • pwpush
  • Custom image
• Heroku
• Digital Ocean
  • App Platform
  • Kubernetes Service
• Microsoft Azure
  • App Service
  • Container Instances (ACI)
  • Kubernetes Service (AKS)
• Google Cloud
  • App Engine
  • Cloud Run
  • Kubernetes Engine
• AWS
  • Elastic Container Service (ECS)
  • Kubernetes Service (AKS)
• Source Code
• Other (please specify)

If applicable, what version of Password Pusher?

1.47.3

Screenshots

The error:

/opt/PasswordPusher/vendor/bundle/ruby/3.3.0/gems/irb-1.14.1/lib/irb.rb:1260:in `full_message': Network unreachable (Errno::ENETUNREACH)

📈 Expected behavior

I expect an email to be sent :)

📎 Additional context

Since IPv6 is always a bit tricky, I had to define a subnet explicitly in my docker-compose.yml file:

networks:
  default:
    enable_ipv6: true
    ipam:
      config:
        - subnet: fd40:3457:518e:725b::/64

If I set the subnet to 2001:db8::/64 (the prefix reserved for documentation), it works. I would also like to point out that networking works, I just have reason to believe that the application prioritizes IPv4, which doesn't work on that host+container.

I tried to define the SMTP server by IP address only, but that doesn't work.