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a0ee472501
"Brief" summary/overview of changes. See the PR discussion or individual commits from the PR for more details.
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Only applies to the `docs/content/**` content (_and `setup` command_). `target/` and `test/` can be normalized at a later date.
* Normalize to `example.com`
- Domains normalized to `example.com`: `mywebserver.com`, `myserver.tld`, `domain.com`, `domain.tld`, `mydomain.net`, `my-domain.tld`, `my-domain.com`, `example.org`, `whoami.com`.
- Alternative domains normalized to `not-example.com`: `otherdomain.com`, `otherdomain.tld`, `domain2.tld`, `mybackupmx.com`, `whoareyou.org`.
- Email addresses normalized to `admin@example.com` (in `ssl.md`): `foo@bar.com`, `yourcurrentemail@gmail.com`, `email@email.com`, `admin@domain.tld`.
- Email addresses normalized to `external-account@gmail.com`: `bill@gates321boom.com`, `external@gmail.com`, `myemail@gmail.com`, `real-email-address@external-domain.com`.
- **`faq.md`:** A FAQ entry title with `sample.domain.com` changed to `subdomain.example.com`.
- **`mail-fetchmail.md`:** Config examples with FQDNs for `imap`/`pop3` used `example.com` domain for a third-party, changed to `gmail.com` as more familiar third-party/external MTA.
* Normalize config volume path
- Normalizing local config path references to `./docker-data/dms/config/`: `./config/`, `config/`, \``config`\`, `/etc/` (_volume mount src path prefix_).
- Normalize DMS volume paths to `docker-data/dms/mail-{data,state,log}`: `./mail`, `./mail-state` `./data/mail`, `./data/state`, `./data/logs`, `./data/maildata`, `./data/mailstate`, `./data/maillogs`, (_dropped/converted data volumes: `maildata`, `mailstate`_).
- Other docker images also adopt the `docker-data/{service name}/` prefix.
* `ssl.md` - Use `dms/custom-certs` where appropriate.
* Apply normalizations to README and example `docker-compose.yml`
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Common terms, sometimes interchangeably used or now invalid depending on context: `mail`, `mail container`, `mail server`, `mail-server`, `mailserver`,`docker-mailserver`, `Docker Mailserver`.
Rough transformations applied to most matches (_conditionally, depending on context_):
- 'Docker Mailserver' => '`docker-mailserver`'
- 'mail container' => '`docker-mailserver`' (_optionally retaining ' container'_)
- 'mail server' => 'mail-server' / '`docker-mailserver`'
- 'mail-server' => '`docker-mailserver`'
- 'mailserver' => 'mail-server' / '`docker-mailserver`'
Additionally I checked `docker run` (_plus `exec`, `logs`, etc, sub-commands_) and `docker-compose` commands. Often finding usage of `mail` instead of the expected `mailserver`
Additionally changes `mailserver` hostname in k8s to `mail` to align with other non-k8s examples.
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* drive-by revisions
Mostly minor revisions or improvements to docs that aren't related to normalization effort.
60 lines
2.4 KiB
Markdown
60 lines
2.4 KiB
Markdown
---
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title: 'Best Practices | SPF'
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hide:
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- toc # Hide Table of Contents for this page
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---
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From [Wikipedia](https://en.wikipedia.org/wiki/Sender_Policy_Framework):
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!!! quote
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Sender Policy Framework (SPF) is a simple email-validation system designed to detect email spoofing by providing a mechanism to allow receiving mail exchangers to check that incoming mail from a domain comes from a host authorized by that domain's administrators. The list of authorized sending hosts for a domain is published in the Domain Name System (DNS) records for that domain in the form of a specially formatted TXT record. Email spam and phishing often use forged "from" addresses, so publishing and checking SPF records can be considered anti-spam techniques.
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!!! note
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For a more technical review: https://github.com/internetstandards/toolbox-wiki/blob/master/SPF-how-to.md
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## Add a SPF Record
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To add a SPF record in your DNS, insert the following line in your DNS zone:
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```txt
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; MX record must be declared for SPF to work
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example.com. IN MX 1 mail.example.com.
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; SPF record
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example.com. IN TXT "v=spf1 mx ~all"
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```
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This enables the _Softfail_ mode for SPF. You could first add this SPF record with a very low TTL.
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_SoftFail_ is a good setting for getting started and testing, as it lets all email through, with spams tagged as such in the mailbox.
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After verification, you _might_ want to change your SPF record to `v=spf1 mx -all` so as to enforce the _HardFail_ policy. See http://www.open-spf.org/SPF_Record_Syntax for more details about SPF policies.
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In any case, increment the SPF record's TTL to its final value.
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## Backup MX, Secondary MX
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For whitelisting a IP Address from the SPF test, you can create a config file (see [`policyd-spf.conf`](https://www.linuxcertif.com/man/5/policyd-spf.conf)) and mount that file into `/etc/postfix-policyd-spf-python/policyd-spf.conf`.
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**Example:**
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Create and edit a `policyd-spf.conf` file at `docker-data/dms/config/postfix-policyd-spf.conf`:
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```conf
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debugLevel = 1
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#0(only errors)-4(complete data received)
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skip_addresses = 127.0.0.0/8,::ffff:127.0.0.0/104,::1
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# Preferably use IP-Addresses for whitelist lookups:
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Whitelist = 192.168.0.0/31,192.168.1.0/30
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# Domain_Whitelist = mx1.not-example.com,mx2.not-example.com
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```
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Then add this line to `docker-compose.yml`:
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```yaml
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volumes:
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- ./docker-data/dms/config/postfix-policyd-spf.conf:/etc/postfix-policyd-spf-python/policyd-spf.conf
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```
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