[FR] Add config option to skip cert validation/verification for SMTP about alertmanager

[sathieu]

You can already use:

receivers:
  - name: myreceiver
    email_configs:
      - to: '[email protected]'
        tls_config:
          insecure_skip_verify: true

... but this is per-receiver. An option is needed for global SMTP tls_config.

[TheMeier]

Independent of the pending improvement for global smtp tls config, i think there is nothing to do here.
So please consider clonsing @rahilarious

[TheMeier]

Also instead of disabling tls_verify I would encourage you to use ca_file

[rahilarious]

I have a SMTP server with invalid cert. (accessing via different IP than where domain points to)

For example certificate is for mail.blabla.com which resolves to 122.34.56.78 and one want to access it local ip 192.168.1.5. But accessing locally will say certificate is invalid. There needs to option to skip that verification.

As a workaround I added DNS record in host file in my container (docker/podman) with switch --add-host mail.blabla.com:192.168.1.5. You can also do it in Kubernetes/podman pods with hostAliases. This solves it.

[sathieu]

I created #3732, with:

global:
  smtp_from: '[email protected]'
  # smtp_smarthost: 'mail.blabla.com:465'
  smtp_smarthost: '10.0.0.1:465'
  smtp_auth_username: '[email protected]'
  smtp_auth_password: 'randompasss'
  smtp_require_tls: false
  smtp_tls_config:
    insecure_skip_verify: true
  
receivers:
  - name: myreceiver
    email_configs:
      - to: '[email protected]'