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DNSsy Report

DNS Propagation Checker
I saw several references on websites that this class should be avoided like the plague, and I can agree with this. Searching our resource database to find your matches Follow ServerWatch on Twitter and on Facebook. Which topic are you interested in? I started by trying to use some of the DNS classes but gave up because they were too slow or too constrained. Thank you Regards Paul.

DNS Lookup

Test Your DNS Response Times with DNS Tester

When a DNS request is made, the returned answer is cached by the DNS server so that the second time a DNS request is made, then another request will return the result immediately because of local caching. First, make a random three character alphabetic string. I can imagine that some people will cringe at this blatant misuse of a function, but it was quick! Then, duplicate names are removed and the domain names are used for the DNS requests. The current time is saved before the DNS requests are sent so that the delta time can be calculated.

A DNS packet contains two bytes at the beginning to enable the requester to keep track of the answers, called transactionID. These bytes are set to " Q1 " or " Q2 " for the request. This is a little unorthodox, but when an answer is received, this allows easy checking of whether the received packet is relevant to this program and determines the DNS server that has responded. When answers are received, they are checked as valid " Q1 " or " Q2 " and decoded. The request made is added to the listview and displayed.

If no more answers arrive after timeout, then we can analyse the data and test again. An excellent CodeProject article " C. At first look, these methods looked too difficult for me, so I tried a few other ways of checking DNS. I started by trying the Dns. Resolve method, and also tried Dns. Resolve method uses the computer defined DNS. I experimented with using netsh to change the DNS, but I found that this seemed to take several seconds. Then, I got a hint on the net from Eric Meyers on www.

This seemed to be a way around the inability of Dns. Resolve to use multiple DNS servers, but I found that I could not call this with window minimized for some reason. At this time, I also saw that using these ideas to check the DNS of 30 or 40 names would be very time consuming at several seconds per check.

I moved over to the UdpClient class. Receive would not work for me. There seemed to be no way to stop listening! I saw several references on websites that this class should be avoided like the plague, and I can agree with this.

I finally came back to the socket class, and got it working for me. One tool that I found extremely helpful was Ethereal. It is an open source Ethernet protocol analyser which is available for download here. I have found that the best public DNS is 4. If it does not answer, I consider this a failure. Based on my results so far, I think that this tool can show you the best DNS to use. There is some blocking while the DNS results are received, and so my next projects with the socket will try asynchronous sockets.

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below. Articles Quick Answers Messages. Charles Putney , 27 Mar Please Sign up or sign in to vote. Check the response times of your DNS and compare with other servers. Download demo project - 8.

Background Recently, I had problems with web pages not displaying the first time they were used. The sequence of queries is: Ask the primary DNS to resolve the name. If times out after 1 second with no response, ask the secondary DNS.

Using the code When a DNS request is made, the returned answer is cached by the DNS server so that the second time a DNS request is made, then another request will return the result immediately because of local caching. ToChar random[i] ; if Letters. Close ; Now, parse this received web page for web addresses ending in ".???.

Points of interest An excellent CodeProject article " C. History 28 Mar - Updated source download. A list of licenses authors might use can be found here. My first experiences with computing was with a Bendix G15 drum computer at Carnegie Mellon. I have done microprocessor programming and design for , Z80, and I have moved to C now and am still struggling to understand this.

A Solution Blueprint for DevOps. Protocol Buffer-A beginner's walk through. You must Sign In to use this message board. Charles Putney Jul 6: Charles Putney Dec Mark Dods Jul Charles Putney Dec 2: Shawn McClelland Jun 9: Charles Putney Jun Fan Feng 3-Sep Charles Putney 6-Sep Fan Feng 6-Sep Charles Putney 3-May Paul Betteridge Apr 0: Paul Betteridge 3-May Charles Putney 4-May 1: Charles Putney Mar Keeping it Simple xkxhx1 Dec I like the no-frills approach to this tester; it leaves room for others to code additional features as needed.

Excel Analysis ebloch Jul 9: Is there a way to do this? Excel Analysis Charles Putney Jul 6: Unfortunately, I did not consider this when I did the program.

Excel Analysis ebloch Jul How do I do that? Excel Analysis dbjohnson2 Dec I agree with ebloch. How can I take the test results and import them into an Excel spreadsheet? Excel Analysis Charles Putney Dec The only way I can think of is to add code to create a text file and then save the data.

Once saved, it can be loaded and converted by Excel. Have you seen this tester? It looks pretty good. In the end, it will provide a prioritized list of three server addresses it recommends. Then on the Nameservers tab you can see the list of servers that will be tested, along with their IP address and hostname. On the Owner sub-tab you can see the server IPs along with the company's name. On the Status sub-tab you can see which servers are responding. On the Response Time sub-tab you'll see a performance bar chart summarizing each DNS server's performance after testing is complete.

You can also enter specific addresses of other servers, or use DNS Benchmark's feature for finding the top fastest After starting the benchmark testing, you can see real-time results on the Tabular Data sub-tab. Then when complete, the final results will be shown along with personalized recommendations. GRC's tool instead checks speeds by resolving the domains from the top 50 websites, but that list is customizable.

Though a DNS service may advertise faster browsing if you utilize their nameservers rather than the default ones provided by your ISP, actual speeds can significantly vary depending upon your location and the sites you visit. But if you use a certain service for a particular reason — if it provides content filtering or ad blocking, for example — you may not have much of a choice. Eric Geier is a freelance tech writer -- keep up with his writings on Facebook. Follow ServerWatch on Twitter and on Facebook.

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