Web Tools
TTL (Time to Live)
The TTL is not configured locally in the caching server but is set in the authoritative server and passed along with the information itself. This way the administrator of a domain, can control how long it takes for any change to be known throughout the Internet. By carefully choosing values, one can set the trade off between being able to change things rapidly on the one hand and minimising computing and networking resources needed by name servers on the other hand. If particular information is not expected to change in the near future one can have a high TTL and information known to change soon can be transmitted with a low TTL. It is standard practice to reduce the TTL transmitted with information that is scheduled to change in order to make that change visible rapidly throughout the Internet; once the change has happened the TTL is increased again.
| ARPA | Address and Routing Parameter Area. |
| DDNS | Dynamic DNS |
| DKIM | DomainKeys Identified Mail |
| DNSSEC | Domain Name System Security Extensions |
| IANA | Internet Assigned Numbers Authority |
| ICANN | Internet Corporation for Assigned Names and Numbers |
| InterNIC | Internet Network Information Center |
| PTR | Pointer record |
| SOA | Start of Authority |
| SPF | Sender Policy Framework |
| URL | Uniform Resource Locator |
- Forwards subdomain to a target URL
*216.239.32.21 is a machine in the Google data center that matches website requests against a database of all the websites Google hosts.
If a match is found, then 216.239.32.21 redirects the user to the correct website.
website data is not stored on a single machine with an address, but is virtually stored in Google's network of data centers across the globe. This is the reason you cannot look it up with an ip address.
302 Moved Temporarily
-A 302 redirect is a temporary redirect.
-A 302 Moved Temporarily is cached depending on whether or not it contains a Cache-Control or Expires header.
If neither of these headers is present in the response, the 302 is treated as uncacheable.
For 301 redirect, If users change the forwarding records, it will need a longer time to be updated because of browser’s cache.
Circular Dependency
For example, if the authoritative name server for example.org is ns1.example.org, a computer trying to resolve www.example.org first resolves ns1.example.org. Since ns1 is contained in example.org, this requires resolving example.org first, which presents a circular dependency.
To break the dependency, the nameserver for the org top level domain includes glue along with the delegation for example.org. The glue records are address records that provide IP addresses for ns1.example.org. The resolver uses one or more of these IP addresses to query one of domain's authoritative servers, which allows it to complete the DNS query.
https://domains.google.com/nic/update
Example request:
https://username:password@domains.google.com/nic/update?hostname=subdomain.yourdomain.com&myip=1.2.3.4
Cloud computing involves deploying groups of remote servers and software networks that allow centralized data storage and online access to computer services or resources.
Google Cloud DNS is a high-performance, resilient, global DNS service that provides a cost-effective way to make your applications and services available to your users. This programmable, authoritative DNS service can be used to easily publish and manage DNS records using the same infrastructure relied upon by Google.
Google Cloud DNS lets you publish your zones and records in the DNS without the burden of managing your own DNS servers and software. You use the gcloud tool or the REST API directly to work with Cloud DNS.
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