SixOrNot

Download

You can download SixOrNot from the Mozilla Addons page.

Introduction

SixOrNot is a Firefox extension which makes it easy for you to identify when the website you're connecting to supports the current generation Internet Protocol (version 6). It also allows you to see a list of all the servers contacted to load a page, along with the IP address your browser connected to to do so. DNS information about each server is also available so that you can see if a site could potentially be loaded via IPv6 if your local connection supported it (or to identify when connections were performed via IPv4 when they shouldn't have been). Also shown is information about any proxy used for the connection, and whether Trusted Recursive Resolver (TRR) was used to query DNS.

The SixOrNot icon can be displayed via an address bar icon or a button (which may be placed wherever you like in the Firefox UI). The icon indicates whether the main domain of the site you are viewing supports IPv6 and whether your browser used IPv6 to connect to it. SixOrNot looks at each connection Firefox makes and notes whether it was made using IPv4 or IPv6, the information is then displayed via a handy tooltip.

Interface

Overview

The SixOrNot interface consists of an icon displayed either in the address bar or as a button. By default the address bar icon is disabled and the button is placed onto the navigation bar. You can move the button anywhere you like by entering the Firefox UI customisation mode and dragging it to the desired location. Whether accessed through the button or address bar icon the functionality is identical. Upon clicking the button/icon a tooltip panel is displayed which shows information about the site you are connecting to.

The main icon permits you to see at-a-glance whether the current site supports IPv6 and whether you are connecting to it via IPv6. See below for an explanation of each icon.

For each domain contacted to load the current page a listing appears on the panel. The main domain of the site is displayed in bold text. The first line for each host entry tells you which hosts (by IP address) were used to load the page. This may include resources loaded from the local browser cache. The remaining addresses are those retrieved from DNS records for the domain.

Subsequent entries in the list are for domains which additional resources have been loaded from, e.g. images from content delivery networks. Again, the first address is the actual connection, the rest are from DNS. You can click on the [+XX] link to expand DNS information for the secondary connections, and then click on the [ - ] link to hide them again. The number to the left of the domain indicates the total number of connections made to that domain while loading this page.

Each entry has a count of requests made, and may include additional informational icons as described below.

The SixOrNot interface consists of an icon displayed either in the address bar or as a button. By default the address bar icon is disabled and the button is placed onto the navigation bar. You can move the button anywhere you like by entering the Firefox UI customisation mode and dragging it to the desired location. Whether accessed through the button or address bar icon the functionality is identical. Upon clicking the button/icon a tooltip panel is displayed which shows information about the site you are connecting to.

Icon Meanings

  • This icon indicates that a proxy was used for the most recent connection to this host. On mouseover the tooltip gives information about the type of proxy used, as well as a warning if DNS lookups were disabled (see proxy section below).
  • This icon indicates that DNS resolution for this host made use of the Trusted Recursive Resolver mechanism - see https://wiki.mozilla.org/Trusted_Recursive_Resolver for more details.
  • This icon indicates that Firefox connected to this domain using IPv4 and only A (IPv4) records were returned for the domain. Either your DNS is not capable of returning AAAA records or (more likely) the domain in question supports only the legacy version of the Internet Protocol suite. Why not ask why they haven't upgraded yet?
  • This icon indicates that Firefox connected to this domain using IPv6 and both AAAA (IPv6) and A (IPv4) records were found for the domain in DNS. You should only ever see this icon if you have IPv6 connectivity on your machine.
  • This icon indicates that Firefox connected to this domain using IPv4 and both AAAA (IPv6) and A (IPv4) records were found for the current domain. While the remote domain does support IPv6 your browser did not use it to connect. Typically this means you do not have IPv6 connectivity on your machine, but even if you do sometimes IPv4 is used instead for connections.
  • This icon indicates that Firefox connected to this domain using IPv6 and only AAAA (IPv6) records were found for the domain in DNS. This generally means that the domain in question only supports IPv6. You should only ever see this icon if you have IPv6 connectivity on your machine.
  • This icon indicates that Firefox retrieved all objects in the current page from this domain from local cache (no external connections were made). Only A (IPv4) records were found for this domain in DNS, indicating that the domain is probably available only via IPv4.
  • This icon indicates that Firefox retrieved all objects in the current page from this domain from local cache (no external connections were made). Both AAAA (IPv6) and A (IPv4) records were found for this domain in DNS, indicating that the domain is IPv6 capable.
  • This icon indicates that Firefox retrieved all objects in the current page from this domain from local cache (no external connections were made). Only AAAA (IPv6) records were found for this domain in DNS, indicating that the domain is probably available only via IPv6.
  • This icon indicates that an HTTP/HTTPS proxy was used for this connection. With these types of proxies no information is available about the connection made to the host (since Firefox connects to the proxy which then forwards the request). For these types of proxy DNS lookups are also disabled to avoid leaking information about sites visited.
  • This icon indicates an error occurred for the domain in question.
  • This icon can mean a variety of things, generally it indicates that no IP address information exists for the current location or that there was a failure obtaining it. Try navigating to a website and ensuring you are not using a Proxy and that Offline mode isn't enabled.

Examples

This screenshot shows a typical display for the SixOrNot panel where you are browsing using an IPv4-only connection. The main domain is www.mozilla.org, which was loaded from the local browser cache (with a total of 11 requests), and has only A (IPv4) records in DNS. The main app icon is the same as the main domain icon in the panel. Two additional hosts were contacted to render this page, www.googletagmanager.com (loaded from Cache, DNS retrieved using TRR, the DNS records are currently hidden - you can view them by clicking the [+2] text - the icon indicates that the domain has both A (IPv4) and AAAA (IPv6) DNS records). www.google-analytics.com was loaded partly from cache, and partly from the host via IP address 216.58.206.78 - with a total of 3 requests made. DNS results include A and AAAA records, with the IP addresses listed.

Something important to note is that on an IPv4-only connection sometimes DNS won't give you AAAA records for hosts. This is sytem/configuration dependant.

Screenshot of the SixOrNot panel showing results for a visit to the Mozilla website

Another example, here all connections are made over IPv6.

Screenshot of the SixOrNot panel showing results for a visit to the Google homepage using only IPv6

SixOrNot Licence

Copyright © 2008-2020 Ashley Baldock. All Rights Reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

3. The name of the author may not be used to endorse or promote products derived from this software without specific prior written permission from the author.

4. Products derived from this software may not be called "SixOrNot" nor may "SixOrNot" appear in their names without specific prior written permission from the author.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.