majorlinux
016072e972
- New article: firewalld mail ports wiped after reload (IMAP + webmail outage) - New article: Plex 4K codec compatibility (Apple TV) - New article: mdadm RAID recovery after USB hub disconnect - Updated yt-dlp article - Updated all index files: SUMMARY.md, index.md, README.md, category indexes - Article count: 41 → 42 Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
71 lines
2.9 KiB
Markdown
71 lines
2.9 KiB
Markdown
# firewalld: Mail Ports Wiped After Reload (IMAP + Webmail Outage)
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If IMAP, SMTP, and webmail all stop working simultaneously on a Fedora/RHEL mail server, firewalld may have reloaded and lost its mail port configuration.
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## Symptoms
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- `openssl s_client -connect mail.example.com:993` returns `Connection refused`
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- Webmail returns connection refused or times out
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- SSH still works (port 22 is typically in the persisted config)
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- `firewall-cmd --list-services --zone=public` shows only `ssh dhcpv6-client mdns` or similar — no mail services
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- Mail was working before a service restart or system event
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## Why It Happens
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firewalld uses two layers of configuration:
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- **Runtime** — active rules in memory (lost on reload or restart)
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- **Permanent** — written to `/etc/firewalld/zones/public.xml` (survives reloads)
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If mail ports were added with `firewall-cmd --add-service=imaps` (without `--permanent`), they exist only in the runtime config. Any event that triggers a `firewall-cmd --reload` — including Fail2ban restarting, a system update, or manual reload — wipes the runtime config back to the permanent state, dropping all non-permanent rules.
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## Diagnosis
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```bash
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# Check what's currently allowed
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firewall-cmd --list-services --zone=public
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# Check nftables for catch-all reject rules
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nft list ruleset | grep -E '(reject|accept|993|143)'
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# Test port 993 from an external machine
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openssl s_client -connect mail.example.com:993 -brief
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```
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If the only services listed are `ssh` and the port test shows `Connection refused`, the rules are gone.
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## Fix
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Add all mail services permanently and reload:
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```bash
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firewall-cmd --permanent \
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--add-service=smtp \
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--add-service=smtps \
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--add-service=smtp-submission \
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--add-service=imap \
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--add-service=imaps \
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--add-service=http \
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--add-service=https
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firewall-cmd --reload
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# Verify
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firewall-cmd --list-services --zone=public
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```
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Expected output:
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```
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dhcpv6-client http https imap imaps mdns smtp smtp-submission smtps ssh
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```
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## Key Notes
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- **Always use `--permanent`** when adding services to firewalld on a server. Without it, the rule exists only until the next reload.
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- **Fail2ban + firewalld**: Fail2ban uses firewalld as its ban backend (`firewallcmd-rich-rules`). When Fail2ban restarts or crashes, it may trigger a `firewall-cmd --reload`, resetting any runtime-only rules.
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- **Verify after any firewall event**: After Fail2ban restarts, system reboots, or `firewall-cmd --reload`, always confirm mail services are still present with `firewall-cmd --list-services --zone=public`.
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- **Check the permanent config directly**: `cat /etc/firewalld/zones/public.xml` — if mail services aren't in this file, they'll be lost on next reload.
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## Related
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- [Linux Server Hardening Checklist](../../02-selfhosting/security/linux-server-hardening-checklist.md)
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- [Mail Client Stops Receiving: Fail2ban IMAP Self-Ban](fail2ban-imap-self-ban-mail-client.md)
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