Google Public DNS

Open discussion regarding technological or telecommunication issues
NetworkAdmin
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Google Public DNS

Post by NetworkAdmin » Fri Dec 04, 2009 12:49 pm

Anyone trying this?

http://code.google.com/speed/public-dns/

I have just changed my DNS settings to it, can't really tell any difference - which is a successful result.

There is always going to be a problem for local DNS names mapping to private IP addresses though, and if it gained widespread adoption, it would really stuff up captive portals and other similar services.

thomashouseman
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Re: Google Public DNS

Post by thomashouseman » Fri Dec 04, 2009 1:19 pm

Why? Is there something wrong with exetel's service? :mrgreen:

Seriously though the only time I ever changed mine was when Exetel's fell over for an evening. I used the openDNS one and it stole all my Google searches and returned search entries from their own web crawler instead. Whilst I thought it was quite clever of them, I DID NOT like that. Are google doing something similar?

T.

cubic
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Re: Google Public DNS

Post by cubic » Fri Dec 04, 2009 2:04 pm

Interesting. I've used OpenDNS and Level3's public dns in the past when I had problems with Exetel's Akamai servers, but Google's using anycast so these should give better latency. (And they do, a bit - 150ms here, so still not ideal. Singtel Singapore?)

What's Exetel's policy / preference on this? I'd have thought you'd prefer us to use the standard dns to keep as much traffic as possible on your own servers, like Akamai for Ebay etc.
Last edited by cubic on Fri Dec 04, 2009 2:06 pm, edited 1 time in total.
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Orkon
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Re: Google Public DNS

Post by Orkon » Fri Dec 04, 2009 2:05 pm

Code: Select all

>> ping 8.8.8.8

Pinging 8.8.8.8 with 32 bytes of data:

Reply from 8.8.8.8: bytes=32 time=142ms TTL=243
Reply from 8.8.8.8: bytes=32 time=143ms TTL=243
Reply from 8.8.8.8: bytes=32 time=141ms TTL=243
Reply from 8.8.8.8: bytes=32 time=141ms TTL=243

Ping statistics for 8.8.8.8:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 141ms, Maximum = 143ms, Average = 141ms

>> ping 8.8.4.4

Pinging 8.8.4.4 with 32 bytes of data:

Reply from 8.8.4.4: bytes=32 time=143ms TTL=243
Reply from 8.8.4.4: bytes=32 time=142ms TTL=243
Reply from 8.8.4.4: bytes=32 time=143ms TTL=243
Reply from 8.8.4.4: bytes=32 time=143ms TTL=243

Ping statistics for 8.8.4.4:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 142ms, Maximum = 143ms, Average = 142ms

>> ping 220.233.0.4

Pinging 220.233.0.4 with 32 bytes of data:

Reply from 220.233.0.4: bytes=32 time=11ms TTL=57
Reply from 220.233.0.4: bytes=32 time=11ms TTL=57
Reply from 220.233.0.4: bytes=32 time=11ms TTL=57
Reply from 220.233.0.4: bytes=32 time=10ms TTL=57

Ping statistics for 220.233.0.4:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 10ms, Maximum = 11ms, Average = 10ms

>> ping 220.233.0.3

Pinging 220.233.0.3 with 32 bytes of data:

Reply from 220.233.0.3: bytes=32 time=10ms TTL=60
Reply from 220.233.0.3: bytes=32 time=10ms TTL=60
Reply from 220.233.0.3: bytes=32 time=10ms TTL=60
Reply from 220.233.0.3: bytes=32 time=9ms TTL=60

Ping statistics for 220.233.0.3:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 9ms, Maximum = 10ms, Average = 9ms
I think i'll give it as pass.

latency/response time is 12-14 times slower than exetel servers.

While it might be acceptable as a backup, i'll give it a pass.

Scott

vk3xem
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Re: Google Public DNS

Post by vk3xem » Fri Dec 04, 2009 4:52 pm

Looks interesting as a back up to Exetel's DNS. It's a shame we can only use two DNS Servers in windows, I wouldn't mind putting them in after Exetel's.
The views I present are that of my own and NOT of any organisation I may belong to.

73 de Simon, VK3XEM

Mike Agent N040
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Re: Google Public DNS

Post by Mike Agent N040 » Fri Dec 04, 2009 6:59 pm

Hmm, so perhaps I'm an oddball but I often use OpenDNS on new and existing customer connections simply for the automatic anti-malware component. And of course since Exetel's a static IP company it's a piece of cake to turn on a rudimentary porn filter for end users without having to touch their PCs.

I don't think DNS is really that big a bottleneck on the 'net; although it has had it's fair share of vulnerabilities. I suspect this is more of a marketing thing for Google as DNS queries reveal lots about what a user is doing. For example, they'd know what AV you're running, what version of Windows, perhaps what updates you're getting from MS, what IM you're using, every website you visit, if you're a torrenter - heaps of info.
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NetworkAdmin
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Re: Google Public DNS

Post by NetworkAdmin » Fri Dec 04, 2009 7:06 pm

cubic wrote:What's Exetel's policy / preference on this? I'd have thought you'd prefer us to use the standard dns to keep as much traffic as possible on your own servers, like Akamai for Ebay etc.
Sure. But a DNS query is a truly minimal amount of bandwidth, probably not more than 1kbyte all up in the worst case. Versus the cost of multiple resolvers which, as some other kind poster pointed out, are (like any piece of technology) apt to fail at some time or another.

Anyway, the cost is really neither here nor there. At first look I think there will be other problems (from my blog):
* how will it handle captive portal systems?

These are an increasing part of ISP operations, redirecting end user traffic for any number of reasons. End users switching to the Google public DNS servers will cause portal redirects to break, most likely resulting in a hung browser session or 'page not found' error

* how will it handle internal IP address maps for private networks?

Some ISP's, and many corporate networks make extensive use of RFC 1918 IP address space. Company intranets are a prime example. Mapping that through a local DNS resolver is no problem. Completely breaks with a public resolver though.

It is interesting to see a selling point from Google is that is will "Get the results you expect with absolutely no redirection.". I assume, one day, Google plan to make some revenue from this system. I wonder how they plan to do that?

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Re: Google Public DNS

Post by Orkon » Fri Dec 04, 2009 7:51 pm

vk3xem wrote:Looks interesting as a back up to Exetel's DNS. It's a shame we can only use two DNS Servers in windows, I wouldn't mind putting them in after Exetel's.

You can have more than 2 DNS servers in windows.

Go to TCP/IP -> Advanced -> DNS Tab

In the top box - add as many DNS Servers as you want.

Scott

vk3xem
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Re: Google Public DNS

Post by vk3xem » Fri Dec 04, 2009 8:02 pm

Interesting Scott, where is TCP/IP hiding?
The views I present are that of my own and NOT of any organisation I may belong to.

73 de Simon, VK3XEM

Orkon
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Re: Google Public DNS

Post by Orkon » Fri Dec 04, 2009 8:50 pm

vk3xem wrote:Interesting Scott, where is TCP/IP hiding?
Not Sure of what Version of Windows, but using Windows XP

1) Go to Network Connections in the Control Panel (Classic View)
2) Find your Network Card, right click properties
3) The the box headed "This connection uses the following items", find "Internet Protocol (TCP/IP)", hilight it and click properties
4) Click on the Radio Button "Use the Following DNS Server Addresses" and type in 220.233.0.3 and 220.233.0.4 into the pri/sec
5) Click on the Advanced Button
6) Click on the DNS Tab
7) Then Click Add to add more DNS Servers. There should be the 2 Exetel ones in there already.

When finished, Click OK on the "Advanced TCP/IP Settings", then OK on the "Internet Protocol (TCP/IP) Properties", Then Click OK on the Network Card Properties Window.

Scott

CoreyPlover
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Re: Google Public DNS

Post by CoreyPlover » Fri Dec 04, 2009 9:21 pm

One advantage that Google DNS has over OpenDNS is that it does not redirect incorrect URLs to a search portal. I'm going to give it a try and see how it goes

Edit: I'm seeing 20ms less latency that OpenDNS (170ms vs 190ms), but yes, surely Exetel's DNS resolution has lowest latency (40ms for me). So for me, it is a good and easy to remember (8.8.8.8) DNS server to use in place of OpenDNS. I'll leave it one for a week or so and see if I notice any page stalls

Edit 2: Actually, I think using Google Chrome trumps anything else anyway because it implements DNS prefetching. This means that it scans the page and replaces the URL with the IP address on the fly (and behind the scenes), meaning 50-100ms improvements for page loads regardless of DNS server
I am a volunteer moderator and not an Exetel staff member. As with all forum posts, mine do not constitute any "official" Exetel position. Support tickets may be logged via https://helpdesk.exetel.com.au or residentialsupport@exetel.com.au

vk3xem
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Re: Google Public DNS

Post by vk3xem » Sat Dec 05, 2009 12:30 am

Thanks Scott, this can be handy when roaming on lap top and not on Exetel network, as well as if there is a problem with Exetel's DNS servers.
The views I present are that of my own and NOT of any organisation I may belong to.

73 de Simon, VK3XEM

SMA
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Re: Google Public DNS

Post by SMA » Fri Dec 11, 2009 2:38 pm

Edit 2: Actually, I think using Google Chrome trumps anything else anyway because it implements DNS prefetching. This means that it scans the page and replaces the URL with the IP address on the fly (and behind the scenes), meaning 50-100ms improvements for page loads regardless of DNS server
you actually care about your page loading 100ms faster?

I just use exetel's DNS servers and threw in opendns as a third just incase exetel's went down.

CoreyPlover
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Re: Google Public DNS

Post by CoreyPlover » Fri Dec 11, 2009 3:40 pm

SMA wrote:you actually care about your page loading 100ms faster?
You'd be surprised how this can make the pages seems "snappier"

What sometimes happens with DNS fetching is that one request is held up and the page 'stalls' for a few seconds. Pre-fetching reduces this from occurring as frequently so the browsing experience is actually much smoother
I am a volunteer moderator and not an Exetel staff member. As with all forum posts, mine do not constitute any "official" Exetel position. Support tickets may be logged via https://helpdesk.exetel.com.au or residentialsupport@exetel.com.au

David R
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Re: Google Public DNS

Post by David R » Sat Dec 12, 2009 4:56 am

+ 1
prefetching

nothing beats a browser that knows where you are going (fetching a next machine's IP address) for your expected next click, this actually makes a noticeable difference small (in ms/s) though it is. use (FF)+chrome for the win.
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