| Server Header Lookup | GitHub - safe conditional redirect - defense-in-depth with "always" - Insight at janwillemstegink.nl | |
| Settings to optimize are colored orange. | ||
| RFC 1033 forbids the use of CNAME for the registered, apex domain. The apex domain is the main domain without subdomains, such as ‘example.com’. | ||
| CNAME affects subdomain email settings because MX and SPF cannot differ. Upcoming ANAME is flattened CNAME to just A/AAAA. Outsourced hosting can then be safe. | ||
| The www subdomain is not unnecessary. There are some useful aspects. If you are hosting elsewhere, you will need CNAME, as allowed for subdomain www. | ||
| And for a website with a subdomain, HSTS can be set more precisely. An RFC draft from PowerDNS and DNSimple on ANAME - Cloudflare about ANAME - Me about CNAME | ||
| RFC 9116: "The "Expires" field indicates the date and time after which the data contained in the "security.txt" file is considered stale and should not be used (as per Section 5.3)". | ||
| RFC 9116: "It is RECOMMENDED that the value of this field be less than a year into the future to avoid staleness." | ||
| Suggestion 1: The data contained in the "security.txt" file MUST expire on the date and time as in the "Expires" field, due to the desirability of an annual audit cycle. | ||
| Suggestion 2: For the one-off annual cycle check to work, the "Expires" field date and time is maximally 398 (366+31+1) days into the future, equal to the TLS Certificate Lifespan. | ||
| Suggestion 3: Annual audit requires a scheduled date on an office calendar; and customer requests cannot be dealt with if concentrated in one part of the year. | ||
| RFC 6797, 8.1: "If a UA receives more than one STS header field in an HTTP response message over secure transport, then the UA MUST process only the first such header field." | ||
| Strict Transport Security over secure HTTPS is called HSTS. The server header is only compliant, even if it is just a URL redirect, with a functioning HSTS security header. | ||
| Although browsers do not strictly enforce this rule above, the internet.nl tool tests that the URL is also the first URL over HTTPS for a security header to work. | ||
| With multiple HSTS header values - an application can also set a security header - strictly speaking, the first security header applies to the user agent (UA). | ||
| The internet.nl tool does test for an initial header in the initial server header area. | ||
| Web browser Chrome and the securityheaders.com tool, show values from application to server header level. The first value, starting from server header level, should be set. | ||
| Note: The securityheaders.com tool does not test and report correctly on rewrite to HTTPS and redirection. | ||
| General approach: Comply with proper initial reading of security headers from the server header(s), and note the interpretation of a subsequent value from an identical security header. | ||
| First rewrite the URL to HTTPS using the checkbox in the control panel, secondly set security header values, and finally, if applicable, (conditionally) redirect in the 301 or 302 way. | ||
| A server header requires sufficient settings before public Internet access can be used safely. And avoid the HSTS preload list without understanding its implications. | ||
| For search engines in general, a no-indexing statement is necessary to clean up. For deletion in Google Search, even re-registration of the domain may be necessary. | ||
| Note that robots.txt content - for more control over crawling - can block any processing by a search engine, such as the desired removal of search results. | ||
| url | www.url | |
| Retrieved from url on 2025-09-26 at 13:00:01 UTC in 0 seconds. | ||
| initial: not applicable | initial: not applicable | |
| destination: not applicable | destination: not applicable | |
| initial: not applicable | initial: not applicable | |
| destination: not applicable | destination: not applicable | |
| not applicable | not applicable | |
| not applicable | not applicable | |
| not applicable | not applicable | |
| (To name and achieve the desired situation: different AS, AnyCast, DNSSEC algorithm 13, different DNS software) | ||
| Autonomous system IPv4: | Autonomous system IPv4: | |
| Autonomous system IPv6: | Autonomous system IPv6: | |
| Start of Authority: (this is not one of a registrant, second-level or top-level domain) | Start of Authority: (no registrant domain) | |
| not applicable | not applicable | |
| not applicable | not applicable | |
| not applicable | not applicable | |
| not applicable | not applicable | |
| not applicable | not applicable | |
| If unexpectedly unsafe: The always directive in Apache ensures that a header is set, even for error responses. By default, Nginx only sets headers for successful responses (2xx, 3xx). | ||
| not applicable | not applicable | |
| not applicable | not applicable | |