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mirror of https://github.com/tomav/docker-mailserver.git synced 2024-07-19 22:28:36 +02:00
docker-mailserver/docs/content/config/troubleshooting/debugging.md
polarathene 1b971a89cb docs(sync): Add Github Wiki contributions
During the long-lived PR, multiple contributions to the existing Github Wiki were made, this commit applies those here and mentions the files and authors attributed to the changes:

JaapD: dkim.md + forward-only-mailserver-with-ldap-authentication.md

Added corrections to `setup.sh config dkim` command.
Added compatibility warning about 4096-bit key sizes or greater.
Added ldap tip. 

---

fred727-temp: optional-config.md

Added a mention for `user-patches.sh`.

---

Semir Patel: setup.sh.md + debugging.md

Minor corrections. Additionally corrected `tvial` references that had already been updated in this PR series.

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Stefan Neben: kubernetes.md

> Port 25 proxy protocol configuration in master.cf was missing
docs(sync): Add Github Wiki contributions
> IMAP with STARTTLS is also active, so we need that option here as well
docs(sync): Add Github Wiki contribution
2021-03-25 11:49:24 +13:00

65 lines
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
```
## Sent 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