Filter or App to Read Dmarc Reports
DMARC, DKIM and SPF
If you lot are using a custom domain for your email with providers similar mailbox.org or even host your own mail service server, it is likely that y'all came across these terms at some betoken. All iii are technologies for improving due east-mail service security and authentication. Their whole purpose is to ensure that a mail was actually sent by the person who appears to have sent it, i.e. the person mentioned in the mail service's From header. I don't want to go as well much into detail here and only explain each of them very briefly.
SPF
SPF – the Sender Policy Framework – is quite easy to understand. As the owner of a domain, say example.org, you precisely specify in the DNS records of your domain what mail servers, identified by their IPs, are allowed to ship post for that domain. For instance, if you lot set up a TXT record like "v=spf1 ip4:164.68.116.134 a -all", you are telling whatsoever receiving mail server in the world to just have postal service from *.instance.org if the sending SMTP server has that very certain IP and drop all other incoming messages. Of course, y'all have to rely on the receiving server to fulfill its responsibleness of actually performing that DNS lookup and verification.
Syntax of SPF records still goes a bit beyond the in a higher place case and allow for _include_s, which is basically a way of delegating the specification of the actual SPF record to a different domain. This is peculiarly helpful when using external mail providers, every bit you, equally a customer, plainly cannot know every single IP of their outgoing SMTP hosts.
DKIM
The concept of DKIM is similarly straightforward. Its thought is that a sending mail service server, east.g. yours or your mail hoster'due south i, adds a cryptographic signature to all outgoing post. Given the sender's public fundamental, a receiving server tin hands verify that signature and so. To find out the public key belonging to the sending servers of instance.org, that public primal is stored every bit another TXT tape in instance.org's DNS zone. That'southward it.
DMARC
In contrast to the previous two methods, DMARC is not actually used for authentication, but rather for reporting. Information technology is a way to notify a domain owner near what is going wrong out at that place in the cyberspace with regard to e-mail service. DMARC essentially tells (over again, via DNS) receiving mail servers, including GMail, Outlook, GMX, etc., who to send reports about failed SPF and DKIM verifications to. Depending on the bodily implementation, not merely failure notifications are sent, but also regular, summarizing reports, even if all goes well. Moreover, DMARC also specifies an XML-based file format for those reports. You, equally a domain owner, can and so read and understand those reports and take activeness – whatever that might be.
An example for a full DMARC record tin exist found here. I just desire to emphasize ane part of the <tape> section here.
<row> <source_ip>eighty.241.20.xxx</source_ip> <count>i</count> <policy_evaluated> <disposition>none</disposition> <dkim>laissez passer</dkim> <spf>pass</spf> </policy_evaluated> </row> <identifiers> <header_from>wakapi.dev</header_from> </identifiers>
The report (from Google, in this instance) notifies me, owner of wakapi.dev, that one post from the to a higher place IP was received within a certain time span and that both SPF and DKIM checks were alright. Seems similar my DNS records are correct and nobody tried to scam in my name. Perfect.
Configuring DMARC
Setting upwardly SPF and DKIM for your domain is highly recommended, as the chances of your mails being considered spam by a receiver are significantly lower then. After, yous notwithstanding need to ready DMARC. It is probably best to only google how to do that, at that place are many swell posts out there (similar this (High german-linguistic communication) ane).
In essence, you will cease up with a DNS tape similar to this i:
v=DMARC1; p=reject; adkim=r; aspf=r; rua=mailto:dmarc@muetsch.io; ruf=mailto:dmarc@muetsch.io
In the case, whatever postal service server who actively implements DMARC reports, is instructed to ship them to dmarc@muetsch.io. I would recommend to have a separate accost (different from your main address) for DMARC records, to you can easily set upwardly rules similar "move everything addresses to dmarc@mydomain.tld into some IMAP binder and mark it as read".
Aggregation and visualization
Equally can be seen from the example above, DMARC records are a chip unpleasant to read and yous probably practise not want to go through every report (couple per twenty-four hours) manually. Luckily, a quick GitHub search led me to a projection that helps with this, specifically it does:
- Read DMARC reports from your inbox via IMAP
- Parse them
- Persist them into a database
- Visualize them on a website
(Source: https://www.techsneeze.com)
To be precise, the tool is two separate scripts, the parser and the web dashboard.
Database setup
First, you lot will need a MySQL or MariaDB database, which the parser can write to and the dashboard tin read from. If y'all do non already have a running MySQL instance anyhow, you can easily set up i up, e.thousand. using Docker.
docker run -d -p 3306:3306 -e MYSQL_RANDOM_ROOT_PASSWORD = yes -east MYSQL_DATABASE =dmarc -e MYSQL_USER =dmarc -e MYSQL_PASSWORD =sshhh --name mariadb-dmarc mariadb
This command already creates a database and user for y'all. If you don't want to spawn a whole new database instance or don't want to use Docker, you volition have to create the database and user manually.
$ mysql -u root -p
$ Apply dmarc ; $ CREATE USER 'dmarc' @ '%' IDENTIFIED WITH mysql_native_password BY 'sshhh' ; $ GRANT ALL PRIVILEGES ON 'dmarc' . * TO 'dmarc' @ '%' ; $ FLUSH PRIVILEGES ; $ quit ;
Parser setup
The parser tin exist found at techsneeze/dmarcts-report-parser and is written as a single-file Perl script, alongside a configuration file. The repo's README explains the setup process quite well.
In the config file, you need to ready your to a higher place database connection (usually something like imap.yourprovider.com, port 993, SSL) and credentials as well as your IMAP credentials to log in to your mail account. With $imapreadfolder you tell the parser which IMAP folder to search for DMARC mails. This should preferably not exist your inbox' root folder to not distract the parser and non risk losing any mail service. I, personally, set a sub folder dmarc in my inbox (IMAP path is INBOX/dmarc then) and created a rule to automatically put all DMARC mails in there.
Since the parser is a 1-shot script and not a long-running procedure, yous will probably want to invoke it on a regular footing, which you can set a cron job for, using crontab -e
@hourly cd ~/dev/dmarcts-report-parser && ./dmarcts-written report-parser.pl -i
Viewer setup
The viewer / web dashboard is located at techsneeze/dmarcts-study-viewer and implemented as a unproblematic PHP awarding. That ways, you will need a spider web server similar Apache2, nginx or Caddy (I'd recommend the latter) alongside a PHP installation (e.g, using PHP-FPM). Explaining how to set these things up is across the telescopic of this article, but you tin just google it. After putting your database credentials one time again (this fourth dimension for reading), you are good to become.
Striking http://localhost/dmarcts-report-viewer.php (or whatever your domain name is) in your browser and you lot volition be presented a (not that squeamish-looking, but) very convenient and practical web UI to get an overview over all DMARC reports, grouped by domains, recipient providers and date. Much cooler than reading XML files ane by one!
Thanks a lot for the great work past @techsneeze.
Source: https://dev.to/n1try/aggregating-and-visualizing-dmarc-reports-fa5
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