-----BEGIN PUBLIC KEY-----
-----END PUBLIC KEY-----
The synchronization of the DNS servers must be perfect in order to avoid any dns resolution error. The servers must therefore give the same answer when asked "what are the DNS servers for the domain?".
SOA are synchronized
The SOA answered by the DNS servers must be identical for each servers. The most important information is the master server and the contact email address.
SOA email is valid
An email address must respect some conditions to be valid, accordding to the RFC 5322.
DNS resolvers that allow queries from all IP addresses and are exposed to the Internet can be attacked and used to conduct Denial of Service (DoS) attacks on behalf of the hacker.
Transfer zone is disable
An attacker can use a zone transfer that contains a malicious code or an inappropriate format that crashes a DNS server vulnerable to this type of attack, which results in a DoS that destabilizes the DNS services. It is possible to test it manually with this commands: #host -T axfr or #dig axfr.
aspmx.l.google.com with IP [126.96.36.199] does not contain the name of the server.
mx.google.com ESMTP p15si26387272wmq.139 - gsmtp
aspmx2.googlemail.com with IP [188.8.131.52] does not contain the name of the server.
mx.google.com ESMTP bk4si17097348qkb.399 - gsmtp
aspmx3.googlemail.com with IP [184.108.40.206] does not contain the name of the server.
mx.google.com ESMTP q21si18494295ljp.558 - gsmtp
Banner must contain the name of the server
MX servers are accessibles
Smtp servers that are listed in DNS area must be accessible, otherwise, there is a risk that emails may be lost
MX IPs have reverse
When a sending server makes a connection to the recipient server, the recipient server notes the sending IP address and performs a reverse lookup, called a PTR lookup, named after the type of DNS record used. If the result of the reverse lookup matches the result of a forward DNS Lookup, then it's much more likely that the message is legitimate. If the IP address doesn't match, it's much more likely that the sending address was spoofed and therefore much more likely that it's unwanted and could be considered spam.
The domain must have an A field in order for the website to be accessible.
Host "www" have "A" field
WWW host is not required for a website, but it's better to have one.
Domain have "AAAA" field
It is highly recommended to have an IPv6 for the website.
Host "www" have "AAAA" field
If you configure a WWW host for your website, it is recommended to have an IPv6.
HTTP port (80) is open
This test verifies the presence of a website for the given IP or domain. Then scans port 80. If the domain or IP is pointing to a website then port 80 must be open so that it can be accessed from a browser. Otherwise port 80 must be closed.
HTTPS port (443) is open
This test verifies the presence of a website for the given IP or domain. Then scans port 443. If the domain or IP is pointing to a website then port 443 must be open so that it can be accessed from a browser. Otherwise port 443 must be closed.
Web server version is hidden
To avoid giving details to malicious people, the version of the server should not be visible.
Web application technology is hidden
To avoid giving details to malicious people, the technology that supports the application should not be visible.
Cookies are secure
The HTTP Content-Security-Policy response header allows web site administrators to control resources the user agent is allowed to load for a given page. With a few exceptions, policies mostly involve specifying server origins and script endpoints. This helps guard against cross-site scripting attacks (XSS).