The DMARCER crawler
If our crawler reached your site and you want to understand why, slow it down, or stop it, this page tells you exactly how.
What it is
DMARCER operates a web crawler that identifies itself in every request with this user agent:
Mozilla/5.0 (compatible; DmarcerSpotter/1.0; +https://dmarcer.net/bot)
DMARCER measures the email security posture (DMARC, SPF, DKIM and related standards) of domains across the internet and publishes anonymised industry benchmarks. The crawler makes a small number of requests to a site's public home page to read the business details a company already publishes about itself, such as its name, address and contact links.
Why it may have visited your site
Your domain appeared in our public benchmark dataset, so the crawler fetched your home page to read the openly published business information there. It requests public pages only. It does not attempt to log in, submit forms, access private areas, or probe for vulnerabilities.
How it behaves
- It identifies itself. Every request carries the user agent above and a link back to this page.
- It is low volume. It typically requests only your home page, and only occasionally.
- It honours robots.txt. We read your
robots.txtbefore fetching and follow its rules for our crawler. - It never scans or attacks. No port scanning, no vulnerability probing, no login attempts, no automated form submission.
Block it instantly
The fastest way to stop our crawler is to add this to your site's robots.txt file:
User-agent: DmarcerSpotter Disallow: /
We check robots.txt on our visits and cache it only briefly, so a change like this takes effect within a day, with no need to contact us.
Opt out completely
If you would rather we removed your domain from our systems altogether, email abuse@dmarcer.net with the domain name and we will add it to our permanent suppression list. Once suppressed, none of our crawlers will contact your site again.
Who operates it
The crawler is operated by iVibe Media Limited (trading as DMARCER, company no. 17212558). For anything else, including abuse reports, contact abuse@dmarcer.net.
See also our Privacy policy and Security and trust page.