DNS Functioning, Secondary Nameserver and Resource Records
In order to make website or any other web-based service available 24/7 it is crucial to have reliable DNS service. It is because of DNS resolving is starting point of any potential visit of website, mapping human-friendly text-based domain like “www.qu.edu.az” name into computer-friendly IP address like “85.132.19.200”. So, if DNS is failed or too slaw, it may become the bottleneck of the important project. Generally, all web hosting providers, as well as some of domain name registrars, recommend customers to use freely their DNS servers but most of them are not enough reliable. Outsourcing of DNS service to professional DNS hosting provider with multiple DNS servers in multiple geographic locations can be one of the key factors in maintaining of the uptime critical web-projects.
There are several evidential properties of any Internet-based service like DNS service. These properties affirm in general that service is reliable.
Performance – short time of DNS resolving – high performance servers, geographically distributed (most close server responds to client’s request), implement load balancing and redundancy with anycast addressing
Security – protect from DNS specific attacks such as Denial-of-service (DoS) or cache poisoning – encrypt transfers between a primary and a secondary DNS server, forbid recursive DNS servers, use anycast, …
Manageability – provide user-friendly interface – web-based control panel enables management your DNS zone’s all DNS records
Reliability – provide service available 24/7 – all features above will guarantee 100% SLA
Actually all DNS providers decisively claim that their DNS service responds to all mentioned requirements. However, DNS service is too complex and these features are not enough, DNS service should also be useful, flexible and herewith cheap.
Here I will try to specify some additional DNS specific criteria of service which should be kept in mind in order to choose the right DNS service:
Existing of free/trial service (Free/Trial) – possibility to use service for free with restricted options (forever or just a trial term)
Minimal TTL value (TTL) – Time-of-Live, indicates how long resource records information will be stored in cache of the DNS server (critical, if your IP address is changed frequently)
Records per zone (RPZ) – indicate how many resource records (A, NS, CNAME, MX, …) you can add to your zone
Number of hosts/domains per account (Hosts/Domains) – number of A records you can specify for the different hosts of the same domain / how many domains you can add to your account without additional payment
Number of DNS queries per month (DNS queries) – indicates how many resolves per month are allowed for your zone (resolving occurs each time when somebody access to your website, sends email to your domain, …)
Minimal plan price (Min Price) – most cheap DNS service plan
Price of additional queries (+ Queries) – if the number queries provided by your plan is not enough, usually, you can request more
Price of additional domain (+ Domain) – in order to be able to collect all your domains within the same account and manage them all from one point.
The DNS Hosting Service Providers and their estimation in accordance to the mentioned criteria:
| Company | Free/Trial | TTL | RPZ | Hosts/Domains | DNS Queries | Min Price | + Queries | + Domain |
| zoneedit.com | Yes (5 custom domain) | 20 min | 1000 | unlimited/1 | 3000.000 | 12 | 1 | 11 |
| dyndns.com | Yes (hostname in one of 18 domains) | 20 sec | 75 | 30/1 | 600.000 | 15 | 15 | 15 |
| everydns.com | Yes (custom domain) | any | unlimited | 20/1 | 600.000 | 15 | ||
| dnspark.net | Yes (trial) | any | unlimited | unlimited/1 | 5000.000 | 14 | 5.5 | 14 |
| easydns.com | – | 20 sec | – | 1 | 1000.000 | 20 | 2 | 20 |
| dnsmadeeasy.com | Yes (trial) | 5 sec | 40 | 10/3 | 5000.000 | 30 | 1.6 | 2 |
Just in case, it’s third year I’m using dnspark.net DNS service for corporate website and my own need and really happy with it.
Don’t forget DNS service is backbone of your Internet presence and think before entrusting your business to company, which doing this work for free, so offer zero guarantee for service reliability
Abzetdin Adamov's IT Blog 