docker-mailserver/docs/content/config/troubleshooting/debugging.md
polarathene 021e942c4c docs(refactor): Large refactor + additions + fixes
Consistency pass, formatting cleanup and fixes, introduce admonitions, add front-matter.

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docs: Add front-matter

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docs: Fix and format links

- Some links were invalid (eg files moved or renamed)
- Some were valid but had invalid section headers (content removed or migrated)
- Some use `http://` instead of `https://` when the website supports a secure connection.
- Some already used the `[name][reference]` convention but often with a number that wasn't as useful for maintenance.
- All referenced docs needed URLs replaced. Opted for the `[name][reference]` approach to group them all clearly at the bottom of the doc, especially with the relative URLs and in some cases many duplicate entries.
- All `tomav` references from the original repo prior to switch to an organization have been corrected.
- Minor cosmetic changes to the `name` part of the URL, such as for referencing issues to be consistent.
- Some small changes to text body, usually due to duplicate URL reference that was unnecessary (open relay, youtous)
- Switched other links to use the `[name][reference]` format when there was a large group of URLs such as wikipedia or kubernetes. Github repos that reference projects related to `docker-mailserver` also got placed here so they're noticed better by maintainers. This also helped quite a bit with `mermaid` external links that are very long.
- There was a Github Wiki supported syntax in use `[[name | link]]` for `fetchmail` page that isn't compatible by default with MkDocs (needs a plugin), converted to `[name][reference]` instead since it's a relative link.

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docs: Update commit link for LDAP override script

Logic moved to another file, keeping the permalink commit reference so it's unaffected by any changes in the file referenced in future.

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docs: Heading corrections

Consistency pass. Helps with the Table of Contents (top-right UI) aka Document Outline.
docs: codefence cleanup

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docs: misc cleanup

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docs: Add Admonitions

Switches `<details>` usage for collapsible admonitions (`???`) while other text content is switched to the visually more distinct admoniton (`!!!` or `???+`) style.

This does affect editor syntax highlighting a bit and markdown linting as it's custom non-standard markdown syntax.
2021-03-25 11:49:24 +13:00

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2.6 KiB
Markdown

---
title: 'Troubleshooting | Debugging'
---
!!! info "Contributions Welcome!"
Please contribute your solutions to help the community :heart:
## Enable Verbose Debugging Output
You may find it useful to enable the [`DMS_DEBUG`][github-file-env-dmsdebug] environment variable.
## Invalid Username or Password
1. Shell into the container:
```sh
docker exec -it <my-container> bash
```
2. Check log files in `/var/log/mail` could not find any mention of incorrect logins here neither in the dovecot logs.
3. Check the supervisors logs in `/var/log/supervisor`. You can find the logs for startup of fetchmail, postfix and others here - they might indicate problems during startup.
4. Make sure you set your hostname to `mail` or whatever you specified in your `docker-compose.yml` file or else your FQDN will be wrong.
## Installation Errors
During setup, if you get errors trying to edit files inside of the container, you likely need to install `vi`:
```sh
sudo su
docker exec -it <my-container> apt-get install -y vim
```
## Testing Connection
I spent HOURS trying to debug "Connection Refused" and "Connection closed by foreign host" errors when trying to use telnet to troubleshoot my connection. I was also trying to connect from my email client (macOS mail) around the same time. Telnet had also worked earlier, so I was extremely confused as to why it suddenly stopped working. I stumbled upon `fail2ban.log` in my container. In short, when trying to get my macOS client working, I exceeded the number of failed login attempts and fail2ban put dovecot and postfix in jail! I got around it by whitelisting my ipaddresses (my ec2 instance and my local computer)
```sh
sudo su
docker exec -ti mail bash
cd /var/log
cat fail2ban.log | grep dovecot
# Whitelist IP addresses:
fail2ban-client set dovecot addignoreip <server ip> # Server
fail2ban-client set postfix addignoreip <server ip>
fail2ban-client set dovecot addignoreip <client ip> # Client
fail2ban-client set postfix addignoreip <client ip>
# This will delete the jails entirely - nuclear option
fail2ban-client stop dovecot
fail2ban-client stop postfix
```
## Send email is never received
Some hosting provides have a stealth block on port 25. Make sure to check with your hosting provider that traffic on port 25 is allowed
Common hosting providers known to have this issue:
- [Azure](https://docs.microsoft.com/en-us/azure/virtual-network/troubleshoot-outbound-smtp-connectivity)
- [AWS EC2](https://aws.amazon.com/premiumsupport/knowledge-center/ec2-port-25-throttle/)
[github-file-env-dmsdebug]: https://github.com/docker-mailserver/docker-mailserver/blob/master/ENVIRONMENT.md#dms_debug