More About TWDNS

From: What does TreeWalk do? Essentially, putting a "name" into the browser doesn't get you anywhere. The "name" must be translated into machine recognizable numbers (octets) such as 64.233.167.99 which takes you to Google.com (the Google Search Engine).

Note: "DNS" is an acronym for either "Domain Name System" or "Domain Name Server". In some situations "DNS server" has been used here to help clarify the differences. We'll also mention a few of the tools that come with TreeWalk, which are available from the program group (click the "Start" button, select "All Programs" or "Program Files" and navigate to the "TreeWalk" folder to select either the "config" or "tools" icons for more menu choices).

Briefly, let's look at the current make-up of today's Internet and TreeWalk's interaction within that scenario. Most ISPs use the ICANN root name servers and if there is a problem with those servers, that problem reflects right back to your ISP's DNS servers. Perhaps you will get spotty, irregular DNS service and sometimes your ISP's DNS will fail you completely. "TreeWalk DNS" was written by ObiWan and NT Canuck to provide an alternative to total reliance on your ISP's service, by providing localized hostname resolution for common Operating Systems that normally do not have this capability.

How TreeWalk Works

TreeWalk caches DNS results locally, which are stored in RAM before being written to disk so such data is still available after a reboot of your computer. TW checks for a local record of any browser, email, Instant Messenger, FTP, Newsgroup (etc.) request that you initiate. If it doesn't find one, it "goes out and gets one", stores that record to RAM and subsequently writes it to a file for future referencing. TreeWalk can do this through your Internet connection even if your ISP's DNS servers are struggling for any reason. TreeWalk's co-developer, ObiWan, explains things further:

"When TreeWalk receives a query it first checks to see if it already has the requested info in its cache and if the info is still valid and not expired. If that's the case, TW will return the data from the cache. If, on the other hand TW has no info available, it will start by querying the root DNS (root-hints) and proceed walking the DNS tree to find the requested data.

Now let's say a given domain (even the root, or ".") has two or more DNS servers (in the case of "." [root] there are 13 DNS servers) and let's also say it's the first time you run TW... The program won't have any info about the DNS servers' response times so all the servers will have the same "score". TreeWalk will just pick the first DNS server and use it to perform the current query then store the time it took for that server to return an answer and sort the DNS list. This means that the other (still "unscored") servers will come first in the list since their starting value will be "blank". For a second query, TW will pick the first DNS in the list again, process it, store the timing and re-sort the list. This is repeated for every query sent for that domain.

Next, let's assume TW queried and "scored" all the DNS servers for a given domain; when a new query for that domain is requested, TW will pick the first DNS in the list (the "fastest" one), query it, store the time and sort the list once more. This means that as long as a given DNS server for a certain domain will be faster to answer than the others, TW will keep using it. I've over-simplified this explanation but I hope you now understand how TreeWalk DNS "self-tunes" itself to assist speeding up external DNS access."

TreeWalk Installation

The TW install routine moves the Primary DNS server for your ISP into the Alternate DNS server position in your Networking Properties so that if a configuration or other local error interrupts the TW Service, your machine will look to the secondary server in the list (which was formerly your Primary DNS server), and will resolve names through that route instead. Upon uninstalling TW, all your previous settings are restored exactly. If TW was installed properly, you usually shouldn't ever need to uninstall it. If you read and adhere to the information presented by the installer you'll be up and running your own Personal DNS Server quickly and easily, after a simple reboot of your computer!

In the unlikely event that the local TreeWalk server and your ISP's servers all fail to resolve names at the same time, you can still try updating the ICANN root-hints anyway (as a further test) or you can try the ORSN root-hints. If all of the above fails, a call to your ISP might be in order to verify that you currently have Internet Service in your area.

If you use a Root plug-in for TreeWalk, this changes the scenario somewhat. Caching and other features are still enforced but plug-ins use a specific root zone file based on your choice of plug-in. Using a plug-in usually assumes and suggests some type of low-level monitoring, such as in a LAN environment.

Root-hints

Generally you will not need to update any root-hint files, but the authors have provided this capability (and others too) for users who might have a more complicated configuration, like a local LAN server for example. The tools included with TW are more for troubleshooting than anything else and should be left unused by the more basic users as they are not intended as toys to play with. The "Backup" and "Restore Backup" tools should definitely be used to save any working TreeWalk configuration before performing any tests, so that the configuration can be re-instated in case of any unintentional or accidental user error.

This is similar to what you should see if you run the "Update root-hints from ORSC" batch file to update the ORSC root-hints:

Getting file zone.orsc from DNS server 199.166.24.1
Stopping the DNS service daemon
The twdns service is stopping.
The twdns service was stopped successfully.
Replacing file named.root with zone.orsc
        1 file(s) copied.
Deleting file zone.orsc
Zapping the cache file
Starting the DNS service daemon
The twdns service is starting.
The twdns service was started successfully.
All done, check for errors and then
Press any key to continue . . .

The batch file downloads a zone file and updates TreeWalk's named.root file with the content.

This is what you might see if you have a default install of TW and update the ICANN root-hints:

Getting file zone.icann from DNS server 198.41.0.4
Stopping the DNS service daemon
The twdns service is stopping.
The twdns service was stopped successfully.
Replacing file named.root with zone.icann
        1 file(s) copied.
Deleting file zone.icann
Zapping the cache file
Starting the DNS service daemon
The twdns service is starting.
The twdns service was started successfully.
All done, check for errors and then
Press any key to continue . . .

...and similar for ORSN. If you experience any problems with other root-hints switch back to the default ICANN hints.

If you're using a slave-root plug-in you'll see procedures similar to the above, but keep in mind that the plug-ins use their own root database files so whatever servers are listed in named.root will be used for lookups after an uninstall of the plug-in. Only one Root plug-in can be installed at any one time and any existing plug-in needs to be uninstalled before trying another. These add-ons install and uninstall very quickly, with no reboots required.

In either case, you can use TreeWalk rather than simply using and relying on your ISP's servers but the root-slave plug-ins will auto-update themselves at regular intervals. The "Update root-hints from [root]" tools are ineffective and not required when using our plug-ins. If you employ the default install of TW you still have the option of choosing your preferred root zone, but keep in mind that this should be done only as required, for many good reasons.

Forums for TWDNS Support: TreeWalk Support forums and newsgroups provide TreeWalk users with access to shared help and advice. If you're going to post a message asking for help with your TreeWalk problem, please be sure to include specific details about your computer (memory and processor speed), Operating System, connection type (how you connect to the Internet), third party software (anti-virus, anti-Trojan, firewall, anti-scripting, etc.), the version of TreeWalk (or BIND-LE) you're using, networking configuration and hardware, and any relevant error messages. This will aid greatly to find the solution for your problem as soon as possible.

"New, Intermediate and Advanced users of the FREE version of the TreeWalk Personal DNS Caching Server" are invited to join in discussions in the forums and place support questions in the ntc.config.discuss forum. Licensed users should continue to contact the TreeWalk site for private email support but are always encouraged to participate in general discussions or to use the ntc.support.questions forum provided for you. (And, if you've used TreeWalk DNS for a while and approve of all the dedication required to bring this program and it's plug-ins to life, please write a friendly line or two in the ntc.config.discuss forum to tell the World what you think!)