This is the merged requirements from the respective GUI's of ZoneCheck and 
DNSCheck.

Language:
[1.1] The GUI MUST support multiple languages in a standardized and reasonably 
easy-to-understand way (especially to make it easy to add more languages in the 
future).  [1.2] The GUI MUST have a way of identifying preference of connected 
users' language and this SHOULD be implemented on the client side (for example 
using language preference settings from connecting browser).
 [1.3] The GUI MUST have a easily configurable default language as a fallback 
from req [1.2].
 [1.4] The GUI MUST support IDN 2.0 domains as input.
 [1.5] The GUI MUST have an easy-to-understand way to change the language from 
the first page.
 [1.6] When a user has chosen a language the index, faq and results MUST be in 
the chosen language UNLESS specific messages are missing where in such a case 
the default language COULD be used for these, or all, messages.

Usability:
[2.1] The GUI MUST have more than one possible view towards the users and the 
default SHOULD be the most simple one.
 [2.2] The GUI MUST have a view containing the "undelegated"-functionality, this 
view SHOULD be perfectly clear on what this means (for example a small warning 
that notifies the user when presenting undelegated-results).  [2.3] The simple 
view SHOULD highlight found errors and warnings for the test being run.
 [2.4] The simple view SHOULD give the user the possibility to see more 
information about encountered errors from within the simple view, if he/she so 
chooses.  [2.5] The GUI MUST be able to give a simple, summarized verdict on the 
domain being tested (for example; green/yellow/red).
 [2.6] The GUI MUST provide a list with previous runs for the given domain and 
these SHOULD be kept separate between normal and "undelegated" testruns.
 [2.7] The list from [2.6] MUST contain working links to the previous tests and 
these MAY be the same links as created in [4.2].
 [2.8] The GUI MUST be able to run on delegated zones with the zone itself 
exclusively as input (name servers as input is optional)
 [2.9] The GUI MUST be able to run on undelegated zones with the zone and at 
least one name server as input.  [2.10] The GUI MUST be able to support HTML/TXT 
as output and SHOULD be designed with further output formats in mind.
 [2.11] The GUI MUST be able to run with different test profiles (meaning: what 
tests are being run at all).
 [2.12] The GUI MUST be able to show a progress bar with a rough estimate of 
total test progress and it SHOULD also tell the user what specific test is 
currently running.
 [2.13] The GUI MUST be able to stop a test on a fatal error if the user has 
given the GUI input to do so.
 	
Security:
[3.1] The GUI MUST have a chroot-similar design where its config, outside of 
reach of the web root itself, is read only once at startup.
 [3.2] The GUI MUST have all sensitive information in the protected 
configuration file from [3.1] but MAY have options elsewhere if deemed 
necessary.  [3.3] The GUI SHOULD have an easy-to-read source code that is well 
documented and commented.

Functionality:
[4.1] The GUI MUST have the same functionality over IPv6 as is given over IPv4.
 [4.2] The GUI MUST create unique links for every test generated through its 
interface and these links SHOULD be easy to find for the user.
 [4.3] The GUI SHOULD allow links to tests that were generated from other 
sources than the GUI itself but MAY not allow all available sources to be 
accessed.
 [4.4] The GUI MUST be designed so that it is easy to add new tests easily.
 [4.5] The GUI MUST be able to take DS record(s) as input to test DNSSEC 
properly on undelegated domains.
 [4.6] The GUI SHOULD report to the user what IP-address he/she is connecting 
from.
 [4.7] The GUI MUST report what version of the engine was used to generate the 
result(s) displayed.