1. General Results, most used to calculate the result A name "routerr.duckdns.org" is domain, public suffix is ".duckdns.org", top-level-domain is ".org", top-level-domain-type is "generic", tld-manager is "Public Interest Registry (PIR)", num .org-domains preloaded: 5035 (complete: 142558) A good: No asked Authoritative Name Server had a timeout HSTS-Preload-Status: unknown. Domain never included in the Preload-list. Check https://hstspreload.org/ to learn some basics about the Google-Preload-List. X Fatal error: Nameserver doesn't support TCP connection: ns1.duckdns.org: Timeout X Fatal error: Nameserver doesn't support TCP connection: ns1.duckdns.org / 54.187.92.222: Timeout X Fatal error: Nameserver doesn't support TCP connection: ns2.duckdns.org: Timeout X Fatal error: Nameserver doesn't support TCP connection: ns2.duckdns.org / 54.191.117.119: Timeout X Fatal error: Nameserver doesn't support TCP connection: ns3.duckdns.org: Timeout X Fatal error: Nameserver doesn't support TCP connection: ns3.duckdns.org / 52.26.169.94: Timeout X Fatal error: Nameserver doesn't support TCP connection: ns4.duckdns.org: Timeout X Fatal error: Nameserver doesn't support TCP connection: ns4.duckdns.org / 44.242.92.242: Timeout Y routerr.duckdns.org 192.168.2.1 Warning: Private ip address found. No connection possible. There are two types of ip addresses: Worldwide unique, global addresses and private addresses. If you want that other users connect your domain, your domain must have minimal one A- (ipv4) or AAAA- (ipv6) entry with a global ip address. Check https://en.wikipedia.org/wiki/Private_network to understand the details: 192.168.0.0 to 192.168.255.255: Class C - 256 private net, every with 256 addresses Y www.routerr.duckdns.org 192.168.2.1 Warning: Private ip address found. No connection possible. There are two types of ip addresses: Worldwide unique, global addresses and private addresses. If you want that other users connect your domain, your domain must have minimal one A- (ipv4) or AAAA- (ipv6) entry with a global ip address. Check https://en.wikipedia.org/wiki/Private_network to understand the details: 192.168.0.0 to 192.168.255.255: Class C - 256 private net, every with 256 addresses 2. DNS- and NameServer - Checks A Info:: 2 Root-climbing DNS Queries required to find all IPv4- and IPv6-Addresses of 4 Name Servers. A Info:: 2 Queries complete, 2 with IPv6, 0 with IPv4. A Good: All DNS Queries done via IPv6. A Good: Some ip addresses of name servers found with the minimum of two DNS Queries. One to find the TLD-Zone, one to ask the TLD-Zone.ns1.duckdns.org (54.187.92.222), ns2.duckdns.org (54.191.117.119), ns3.duckdns.org (52.26.169.94), ns4.duckdns.org (44.242.92.242) A Good (1 - 3.0):: An average of 0.5 queries per domain name server required to find all ip addresses of all name servers. A Info:: 4 different Name Servers found: ns1.duckdns.org, ns2.duckdns.org, ns3.duckdns.org, ns4.duckdns.org, 4 Name Servers included in Delegation: ns1.duckdns.org, ns2.duckdns.org, ns3.duckdns.org, ns4.duckdns.org, 4 Name Servers included in 1 Zone definitions: ns1.duckdns.org, ns2.duckdns.org, ns3.duckdns.org, ns4.duckdns.org, 4 Name Servers listed in SOA.Primary: ns1.duckdns.org, ns2.duckdns.org, ns3.duckdns.org, ns4.duckdns.org. Error: Different SOA.Primary Name Servers found, different SOA Definitions.: ns1.duckdns.org,ns2.duckdns.org,ns3.duckdns.org,ns4.duckdns.org. A Good: SOA.Primary Name Server included in the delegation set.: ns1.duckdns.org,ns2.duckdns.org,ns3.duckdns.org,ns4.duckdns.org. A Good: Consistency between delegation and zone. The set of NS records served by the authoritative name servers must match those proposed for the delegation in the parent zone. Ordered list of name servers: ns1.duckdns.org, ns2.duckdns.org, ns3.duckdns.org, ns4.duckdns.org A Good: All Name Server Domain Names have a Public Suffix. A Good: All Name Server Domain Names ending with a Public Suffix have minimal one IPv4- or IPv6 address. A Good: All Name Server ip addresses are public. A Good: Minimal 2 different name servers (public suffix and public ip address) found: 4 different Name Servers found Warning: No Name Server IPv6 address found. IPv6 is the future, so your name servers should be visible via IPv6.: 4 different Name Servers found Warning: All Name Servers have the same Top Level Domain / Public Suffix. If there is a problem with that Top Level Domain, your domain may be affected. Better: Use Name Servers with different top level domains.: 4 Name Servers, 1 Top Level Domain: duckdns.org Warning: All Name Servers have the same domain name. If there is a problem with that domain name (or with the name servers of that domain name), your domain may be affected. Better: Use Name Servers with different domain names / different top level domains.: Only one domain name used: Warning: All Name Servers from the same Country / IP location.: 4 Name Servers, 1 Countries: US A Info: Ipv4-Subnet-list: 4 Name Servers, 3 different subnets (first Byte): 44., 52., 54., 4 different subnets (first two Bytes): 44.242., 52.26., 54.187., 54.191., 4 different subnets (first three Bytes): 44.242.92., 52.26.169., 54.187.92., 54.191.117. A Good: Name Server IPv4-addresses from different subnet found: A Good: Nameserver supports Echo Capitalization: 4 good Nameserver X Nameserver Timeout checking EDNS512: ns2.duckdns.org / 54.191.117.119 Nameserver doesn't pass all EDNS-Checks: ns1.duckdns.org: OP100: ok. FLAGS: ok. V1: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. V1OP100: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found, no OPT100 expected, no OPT100 found. V1FLAGS: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. DNSSEC: ok. V1DNSSEC: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. NSID: ok. COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns1.duckdns.org / 54.187.92.222: OP100: ok. FLAGS: ok. V1: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. V1OP100: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found, no OPT100 expected, no OPT100 found. V1FLAGS: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. DNSSEC: ok. V1DNSSEC: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. NSID: ok. COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns1.duckdns.org / 54.187.92.222: OP100: ok. FLAGS: ok. V1: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. V1OP100: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found, no OPT100 expected, no OPT100 found. V1FLAGS: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. DNSSEC: ok. V1DNSSEC: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. NSID: ok. COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns2.duckdns.org: OP100: ok. FLAGS: ok. V1: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. V1OP100: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found, no OPT100 expected, no OPT100 found. V1FLAGS: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. DNSSEC: ok. V1DNSSEC: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. NSID: ok. COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns2.duckdns.org / 54.191.117.119: OP100: ok. FLAGS: ok. V1: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. V1OP100: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found, no OPT100 expected, no OPT100 found. V1FLAGS: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. DNSSEC: ok. V1DNSSEC: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. NSID: ok. COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns2.duckdns.org / 54.191.117.119: OP100: fatal timeout. FLAGS: ok. V1: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. V1OP100: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found, no OPT100 expected, no OPT100 found. V1FLAGS: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. DNSSEC: ok. V1DNSSEC: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. NSID: ok. COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns3.duckdns.org: OP100: ok. FLAGS: ok. V1: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. V1OP100: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found, no OPT100 expected, no OPT100 found. V1FLAGS: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. DNSSEC: ok. V1DNSSEC: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. NSID: ok. COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns3.duckdns.org / 52.26.169.94: OP100: ok. FLAGS: ok. V1: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. V1OP100: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found, no OPT100 expected, no OPT100 found. V1FLAGS: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. DNSSEC: ok. V1DNSSEC: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. NSID: ok. COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns3.duckdns.org / 52.26.169.94: OP100: ok. FLAGS: ok. V1: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. V1OP100: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found, no OPT100 expected, no OPT100 found. V1FLAGS: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. DNSSEC: ok. V1DNSSEC: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. NSID: ok. COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns4.duckdns.org: OP100: ok. FLAGS: ok. V1: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. V1OP100: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found, no OPT100 expected, no OPT100 found. V1FLAGS: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. DNSSEC: ok. V1DNSSEC: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. NSID: ok. COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns4.duckdns.org / 44.242.92.242: OP100: ok. FLAGS: ok. V1: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. V1OP100: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found, no OPT100 expected, no OPT100 found. V1FLAGS: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. DNSSEC: ok. V1DNSSEC: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. NSID: ok. COOKIE: ok. CLIENTSUBNET: ok. Nameserver doesn't pass all EDNS-Checks: ns4.duckdns.org / 44.242.92.242: OP100: ok. FLAGS: ok. V1: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. V1OP100: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found, no OPT100 expected, no OPT100 found. V1FLAGS: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. DNSSEC: ok. V1DNSSEC: SOA NOT expected, but found, BADVER expected, NOERR found, Version 0 expectend and found. NSID: ok. COOKIE: ok. CLIENTSUBNET: ok. A Good: All SOA have the same Serial Number Warning: No CAA entry with issue/issuewild found, every CAA can create a certificate. Read https://en.wikipedia.org/wiki/DNS_Certification_Authority_Authorization to learn some basics about the idea of CAA. Your name server must support such an entry. Not all dns providers support CAA entries. 3. Content- and Performance-critical Checks A Good: Domainname is not on the "Specially Designated Nationals And Blocked Persons List" (SDN). That's an US-list of individuals and companies owned or controlled by, or acting for or on behalf of, targeted countries. It also lists individuals, groups, and entities, such as terrorists and narcotics traffickers designated under programs that are not country-specific. Collectively, such individuals and companies are called "Specially Designated Nationals" or "SDNs." Their assets are blocked and U.S. persons are generally prohibited from dealing with them. So if a domain name is on that list, it's impossible to create a Letsencrypt certificate with that domain name. Check the list manual - https://www.treasury.gov/resource-center/sanctions/sdn-list/pages/default.aspx A Duration: 930184 milliseconds, 930.184 seconds