Simple DNS Plus


General Features

Authoritative and Recursive DNS server (resolver and cache)

All the DNS server features and functionality you need to host DNS for domain names, assign domain name to computers and devices for easy access, create and delegate sub-domains, resolve other domain names on the Internet, speed up Internet access with centralized DNS caching, etc.

High performance DNS server engine and user interface

Great for hosting and managing anywhere from a few domains to +100,000 domains.
The user interface is optimized to handle really large domain name portfolios.

Highly configurable

Simple DNS Plus has options to configure all aspects of the DNS services, including many unique but important options not found in competing products such as the ability to limit recursion by IP address. Options are well organized and easy to manage in a central Options dialog available directly from first toolbar button in the main program window.
Of course the software comes preconfigured with settings that are appropriate for most users.

Remote Management / Windows Server Core

The Simple DNS Plus user interface can be run on a desktop computer connecting to a remote Simple DNS Plus server, making it easy and fast to manage the server without Remote Desktop, VNC, or similar.
You can even remote manage a Simple DNS Plus service running on Windows Server Core (no GUI on server) - details.

Direct support for dynamic IP clients

Simple DNS Plus supports TSIG authenticated dynamic DNS updates.
This update method is more efficient than the HTTP based and other proprietary update methods typically used because it happens directly via the DNS protocol.
Several dynamic IP updater applications can be used with this.
Setup tutorials are provided for DynSite and DirectUpdate.
Simple DNS Plus can also function as a dynamic DNS service for more generic HTTP based update clients either by using the DynDNS Service plug-in or by using a web-server front-end. ASP.NET and classic ASP sample code for this is available here.

Full support for IDNs (internationalized domain names)

In Simple DNS Plus you can enter domain names with native characters directly (no punycode conversion needed), and have an option to display native character or punycoded domain names anywhere in the user interface, and quickly switch between these modes.


Simple DNS Plus has full support for IPv6.

Easy to integrate with other applications

You can create DNS records or entire DNS zones from other applications or web-sites and prompt Simple DNS Plus to dynamically load and use these through our REST / JSON based HTTP API.
In fact you can control pretty much everyhing in the software through the HTTP API.
We provide a Swagger / OpenAPI specification file for the HTTP API to use with a long list of automation tools - for example to generate client code in practically any programming / scripting language.
You can explore, play with and test the HTTP API through Swagger UI. Have a peek at
The HTTP API also supports CORS making it possible to access the HTTP API from javascript on a web-page, SSL for secure connections, and detailed debugging log files.
Simple DNS Plus also allows you to connect with other applications and data from different sources through various plug-ins and can be extended through an open plug-in architecture.

100% .NET managed code / 64 bit

This provides great performance - also on 64 bit computers where Simple DNS Plus runs in native 64 bit mode.
And it is very secure because common security issues such as buffer overruns simply cannot happen.

Simple yet Powerful

What makes Simple DNS Plus "simple" is its easy-to-use user interface and automation features.
All options and settings are available directly from the intuitive Windows user interface.
It provides wizards for common tasks such as setting up new zones, importing data, making bulk updates, etc.
You never need to mess with cryptic configuration files or registry settings.
Novice users can have their DNS server up and running correctly and securely in no time.
But make no mistake - Simple DNS Plus is a very capable and full featured DNS server, and it has plenty of options for expert users to tweak it just the way they want.

Simplified DNS management

Zone version control

Simple DNS Plus stores a number of old versions of each zone (each version identified by a SOA-record serial number). This makes it easy to track changes and to restore a previous version if an update caused trouble. You can view, compare, export, or restore old versions of a zone.

Quick access to standard zone files (RFC1035)

Simple DNS Plus internally stores DNS data in an optimized binary format, but you can always just right-click a zone and select "View/Save as standard zone file...", or use the Export Wizard to export all or a group of zones as standard file.

Quick Zone Wizard / Zone Templates

In one simple dialog, enter the domain name and the IP addresses of the web and mail servers, and click OK.
That's all you need to setup a new zone. The IP addresses can even be pre-filled with default values.
The Quick Zone Wizard is template based and you easily create your own templates with exactly the DNS records etc. you need when setting up now domains. Optionally add input fields and VB.NET code. More details.

Suspending zones

Suspending a zone allows you to temporarily stop serving data for a zone without deleting it.
This can be useful for example if you are hosting the domain name for someone else, and they forgot to pay their bill...
Suspended zones are easily recognized in the user interface with a "paused" icon and a red zone name.
When someone requests a name in a suspended zones, Simple DNS Plus can either respond as if the zone was configured at all, or synthesize a response (redirect to a "domain suspended" web-page), or respond with a error.

Bulk Update Wizard

Quickly and easily update thousands of zones in one quick step:
- Find and replace an IP address.
- Find and replace a host name
- Update DNS record TTL values
- Update zone e-mail servers (MX-records)
- Update zone DNS servers (NS- and SOA-records)
- Update SOA-record data fields
- Promote secondary server to primary (convert all secondary zones to primary)
- Update primary DNS server IP address for secondary zones

Copy zone function

Quickly setup a new zone using any existing zone as a template.

Export / Import Wizards

This makes it very simple to move DNS zones to and from other DNS server implementations using standard formats.

Easy IP-to-Name Mapping dialog for reverse zones

Forget "" and reversing IP address segments.
With the "IP-to-Name Mapping", you simply type the corresponding host name next to each IP address represented by the reverse zone.
An "auto scan" function can scan all forward zones for A-records and automatically create matching reverse records.

"Zone Groups" for easy managements of large domain portfolios

You can arrange zones in custom groups, or by primary/secondary status.

Automatic creation of reverse DNS records

Automatically create/update reverse DNS when an A-record (or AAAA-record) is added or modified.

DNS record and zone comment fields

Enter comments for individual DNS records and zones. For example client account numbers, or reminders about what certain records do, etc.
For DNS records updated dynamically or via DHCP, the comment field will automatically contain a timestamp and other information about the update.

Powerful DNS features

Plug-in system

Simple DNS Plus has a plug-in system for fetching DNS data from various outside sources and providing additional functionality.
Click here for a list of available plug-ins.
The plug-in system is open for users and 3rd parties to develop their own plug-ins (.NET based).

JavaScript plug-in New in v. 9.1

Write your own custom logic for DNS query processing in JavaScript. Your script code runs efficiently via Google's V8 JavaScript engine (the same that powers Chrome and Node.js). More information.

Automatic DNSSEC signing and key rollover

Simple DNS Plus can host DNSSEC signed zones and automatically re-sign zones whenever records are updated and at a configurable interval.
And it can automatically rollover ZSKs - generating new keys and removing old at a configurable interval.
And it includes easy to use GUI tools for DNSSEC signing, managing DNSSEC keys, generating DS-records (registrar DNSSEC delegation), settings, etc.
All this is of course also available through the HTTP API.

Auto resolved alias records (ALIAS)

ALIAS-records are virtual alias records resolved by Simple DNS Plus at at the time of each request - providing "flattened" (no CNAME-record chain) synthesized records with data from a hidden source name. This can be used for different purposes - including solving the classic problem with CNAME-records at the domain apex (for the zone name / for "the naked domain").

Automate secondary DNS servers

A secondary Simple DNS Plus server can be configured as a "super slave" server, meaning that all updates on the primary server are automatically transferred to the secondary. This includes creating and deleting zones.
(On other DNS server, you have to create and delete zones on both primary and secondary servers).
Everything is completely automated - when changes are made in the Record Editor, Simple DNS Plus immediately notifies secondary servers and a Zone Transfer is initiated.
Simple DNS Plus can also be configured as a standard secondary DNS server, and will then automatically check for updates on the primary server.
As everything else in Simple DNS Plus, Zone Transfers are implemented according to the DNS standards (RFCs), and so it is 100% compatible with other standard DNS servers.

NAT IP alias conversion

In DNS responses to LAN clients only, this function changes A-records which are pointing to a public IP address of the NAT router to point to the corresponding private IP address of a local server. This way, for example HTTP requests from LAN clients for local web-sites will go directly to the local web-server instead of via the NAT router (which often does not work).

Round Robin load distribution option

If you have multiple web servers (or other Internet servers), containing identical content, Simple DNS Plus can automatically distribute connection loads across the servers using Round Robin.
Round Robin works on a rotating basis in that one server IP address is handed out, then moves to the back of the list; the next server IP address is handed out, then it moves to the end of the list; and so on, depending on the number of servers being used.

Support for standard dynamic updates

Windows clients (Me/2000 and later) can automatically register themselves in the DNS database.
(IP address permission list per zone).
This includes support for SRV-records used by Microsoft Active Directory.

Incremental Zone Transfers

Simple DNS Plus stores a number of old versions of each zone and can calculate a difference set between the current and an older version, so that secondary DNS servers don't need to zone transfer the entire zone each time there is a change.
This saves both CPU cycles and bandwidth.

Option to redirect abusers (synthesize DNS records for unauthorized users)

When someone (unauthorized) from the Internet tries to resolve outside domain names via your DNS server, Simple DNS Plus can respond with synthesized (false) DNS records, for example to redirect that person to a signup web-page or similar.
This feature is also useful when someone is incorrectly pointing their domain registration to your DNS server - for example an ISP customer who has cancelled their account but not changed the domain registration.

Supports wildcard records ( *.domain-name ) for ALL record types

If you are hosting many sub-domains on the same servers, this feature can be a real time saver.

Redirect DNS requests for non-existing domains (NXDOMAIN)

Typically when you open a non-existing domain name in a web-browser, you either get an error page, or you are redirected to some search web-site controlled by the web-browser company (or DNS registry).
This of course happens all the time because of misspellings and bad links on web-sites.
Now you can take advantage of those failed requests (from any client configured to use your DNS server) by redirecting them to your web-server instead of giving this traffic to the browser companies.

Domain specific DNS forwarding (a.k.a. "conditional forwarding")

You can use forwarding to different DNS servers for different domain names.
This is helpful for example if you wish to be able to resolve both Internet domain names as well as a private domain name hosted on another internal DNS server.

Extended DNS forwarding

You can use this unique option if you need to forward incoming requests from the Internet for certain domains names to another internal DNS server.

Microsoft Active Directory compatibility

Simple DNS Plus supports both the required RFC2782 (SRV records) and RFC2136 (DNS Update), and integrates nicely with Microsoft Active Directory.

Strong security features

DNS over TLS (DoT) / DNS over HTTPS (DoH) New in v. 9.0

Standard DNS queries (UDP/TCP) are sent in plain text, which means anyone "listening" to the network can read them. This is a privacy issue, especially on the first leg between the user device and the resolving DNS server (think coffee shop wifi hotspot).
DNS over TLS (DoT) and DNS over HTTPS (DoH) encrypt DNS queries and responses - to keep user data private and secure.

Protects against DNS spoofing (a.k.a. "cache poisoning")

"DNS spoofing" is a term used for malicious cache poisoning where forged data is placed in the cache of DNS server.
Spoofing attacks can result in serious security problems, for example causing users to be directed to wrong Internet sites or e-mail being routed to non-authorized mail servers.
Simple DNS Plus automatically protects against this in several ways:
- It automatically filters out any response received which does not match a sent request.
- All records in received DNS answers are checked for authority, and records for which the answering DNS server does not have authority are ignored.
- It uses random requests IDs.
- It sends outbound DNS requests from random port numbers (a.k.a. "port randomization").
- It queues identical requests to prevent "birthday attacks".
- It has an option to "Ignore responses not coming from the IP address that request was sent to".
- It has an option to "Ignore responses which do not echo the request question section".
- It has an option to randomize the letter casing of the query name of outgoing DNS requests, and only accept responses which correctly echo this (DNS0X20).

Restrict recursion by client IP address

You can specify exactly which clients (by IP address / subnet) that you want the server to perform recursion for.

Response Filtering stops "DNS rebinding attacks"

Web-browsers generally allow any script, Java object, Flash object, etc. to communicate via HTTP / TCP with the server that served a web-page for as long as that web-page is open in the browser. This is controlled by the host name specified in the web-page URL. A "DNS rebinding attack" is done by having the DNS record for the host name time out very quickly (low TTL and other tricks) and then serve a new IP address for the host name in response to the next DNS request ("rebinding"). The new IP address would be the private/local IP address of an intranet server or device at your location. Now with a bit of scripting, the attacker can in effect use your browser as a gateway to your entire intranet - completely bypassing your firewall. The same type attack may also be possible with other Internet applications that rely on host names for security. Browser companies are taking steps to prevent this in new browser versions, but it is much more efficient and secure to stop this type of attack at the DNS level by filtering out any private/local IP addresses in DNS responses from outside DNS servers.

"Stealth DNS" option

A hacker may use a software utility known as a "DNS port scanner" to search for potential targets. This software sends dummy DNS requests to a range of IP addresses on different service ports simply to register which addresses/ports respond.
Any addresses/ports that responded will then be probed further for possible vulnerabilities.
Simple DNS Plus has a special "stealth" option which makes it invisible to such DNS port scanners, by not responding to a DNS request unless it is for data in local zones or originates from a client offered recursion.

Secure Zone Transfers

Avoid revealing all your server addresses and other potentially sensitive data by limiting who can zone transfer your zones.
Simple DNS Plus supports secure zone transfer (TSIG authenticated). Both zone transfer requests and responses are authenticated so this provides protection in two ways; it prevents unauthorized transfers (only people / servers with the correct key can transfer), and it ensures data integrity on secondary servers (not possible to spoof / inject false data during transfers).
Zone transfers can also be limited by IP address for cases where the secondary DNS server does not support TSIG signed zone transfers (less secure but much better than letting anyone zone tranfer your data).

IP address blocking

Ignore packets from known offenders (by IP address). You specify how long a block should be in effect along with comments about why the IP address was blocked for easy reference. Such comments will also be shown in the log when a requests from the IP address is ignored.
IP addresses that make too many requests to quickly (possible DoS attack) can either automatically be added to to the block list, or be rate limited.
An editable list of trusted IP addresses are not not subject to automatic blocking / rate limiting.

Quick and easy diagnostics

DNS Look Up tool

Including WHOIS, DNS over TLS (DoT) and DNS over HTTPS (DoH) New in v. 9.0
A nice GUI based alternative to "nslookup" and "dig".
Great for testing your installation and troubleshooting all kinds of network problems.
With the "WHOIS" feature, you can check the details (such as name, address and phone) on the owners of a domain name or IP address.

Check Internet Delegations wizard

Lets you automatically test if the NS and SOA records in your local zone data match the actual current delegations on the Internet. This can be very useful both to check for errors and to make sure that you still own the domain names that you think you do. It could also be used for example by ISPs to see if any customers have left them (changed their DNS to another provider).

Cache snapshot viewer

Browse the current DNS cache with this intuitive explorer style tool.

See what's going on behind the scenes - live

The Simple DNS Plus "Active Log View" shows who's requesting what, and how the answers are found in real time.
Everything translated into human readable text.
This is great for troubleshooting all kinds of network problems.
If you are trying to learn how DNS works, this can be a real helper.

Detailed log files

Simple DNS Plus optionally writes all DNS queries and answers to a log file which you can then analyze at your convenience.

Remote logging to Syslog server

Log data can be sent to a remote syslog server using the standard syslog protocol (RFC3164).
This can be useful centralize logging and/or take advantage of various alerting features of syslog server software.

Raw log files for incoming request data

This can be used analyze DNS request traffic for security review or for example to compile usage statistics for domain names, customers, etc.

Windows Performance Counters

Simple DNS Plus supplies 9 different performance counters which can be graphed with the Windows Performance Monitor and polled by other programs such as SNMP tools.

Animated Tray Bar Icon

Simple DNS Plus optionally resides in the tray-bar (next to the clock), so it is out of the way, but always within a click's reach.
The Tray Bar Icon lights up whenever Simple DNS Plus is processing requests, so you will know even when the program is minimized.

DNS record types and RFCs

Standard DNS record types supported


RFCs and drafts supported

RFC1034 Domain Names - Concepts and Facilities.
RFC1035 Domain Names - Implementation and Specification.
RFC1183 New DNS RR Definitions
RFC1706 DNS NSAP Resource Records
RFC1876 Location Information in the DNS (LOC)
RFC1912 Common DNS Operational and Configuration Errors
RFC1995 Incremental Zone Transfer in DNS
RFC1996 A Mechanism for Prompt Notification of Zone Changes (DNS NOTIFY)
RFC2136 Dynamic Updates in the Domain Name System (DNS UPDATE)
RFC2181 Clarifications to the DNS Specification
RFC2308 Negative Caching of DNS Queries (DNS NCACHE)
RFC2317 Classless IN-ADDR.ARPA delegation
RFC2671 Extension Mechanisms for DNS (EDNS0)
RFC2672 Non-Terminal DNS Name Redirection
RFC2782 A DNS RR for specifying the location of services (DNS SRV)
RFC2845 Secret Key Transaction Authentication for DNS (TSIG)
RFC2874 DNS Extensions to Support IPv6 Address Aggregation and Renumbering
RFC3225Indicating Resolver Support of DNSSEC
RFC3403 Dynamic Delegation Discovery System (DDDS) (NAPTR records)
RFC3492 Punycode: A Bootstring encoding of Unicode for Internationalized Domain Names in Applications (IDNA)
RFC3596 DNS Extensions to support IP version 6
RFC3597 Handling of Unknown DNS Resource Record (RR) Types
RFC4033 DNS Security Introduction and Requirements
RFC4034 Resource Records for the DNS Security Extensions
RFC4035 Protocol Modifications for the DNS Security Extensions
RFC4398 Storing Certificates in the Domain Name System (DNS)
RFC4408 Sender Policy Framework (SPF)
RFC4635 HMAC SHA TSIG Algorithm Identifiers
RFC4641 DNSSEC Operational Practices
RFC4701 A DNS Resource Record (RR) for Encoding Dynamic Host Configuration Protocol (DHCP) Information (DHCID RR)
RFC5155 DNS Security (DNSSEC) Hashed Authenticated Denial of Existence
RFC5452 DNS Resilience against Forged Answers
RFC6303 Locally Served DNS Zones
RFC6698 The DNS-Based Authentication of Named Entities (DANE) Transport Layer Security (TLS) Protocol: TLSA
RFC6844 DNS Certification Authority Authorization (CAA) Resource Record
RFC7858 Specification for DNS over Transport Layer Security (TLS) New in v. 9.0
RFC8484 DNS Queries over HTTPS (DoH) New in v. 9.0
DRAFT Service binding and parameter specification via the DNS (DNS SVCB and HTTPS RRs) New in v. 9.0

RFC2131 Dynamic Host Configuration Protocol
RFC2132 DHCP Options and BOOTP Vendor Extensions

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