OpenDNS failing on Slingshot (04)

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TheGreyPilgrim

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#89471 2-Sep-2011 20:22

Have had trouble this evening (ie broken internets!) using OpenDNS. Changing to Slingshot's own DNS servers or Google's DNS works fine. OpenDNS don't list any issues and I can use them no problem via a VPN, so what's up at Slingshot with accessing OpenDNS?

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#515924 2-Sep-2011 20:25

TheGreyPilgrim: Have had trouble this evening (ie broken internets!) using OpenDNS. Changing to Slingshot's own DNS servers or Google's DNS works fine. OpenDNS don't list any issues and I can use them no problem via a VPN, so what's up at Slingshot with accessing OpenDNS?

Do a search on here for the number of posts outlining why there's no benefit to using 3rd party DNS in NZ, and why in fact it almost always makes your experience worse.

Cheers - N

Please note all comments are from my own brain and don't necessarily represent the position or opinions of my employer, previous employers, colleagues, friends or pets.

FreddyK

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#515925 2-Sep-2011 20:26

I experienced this same problem a few days ago, and noted it was out for a couple of hours ... well, I have to admit that a couple of hours past before I changed back to opendns to frind it working again, but with the same problem tonight am also wondering what Slingshot are upto?

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FreddyK

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#515926 2-Sep-2011 20:29

Talkiet:
TheGreyPilgrim: Have had trouble this evening (ie broken internets!) using OpenDNS. Changing to Slingshot's own DNS servers or Google's DNS works fine. OpenDNS don't list any issues and I can use them no problem via a VPN, so what's up at Slingshot with accessing OpenDNS?

Do a search on here for the number of posts outlining why there's no benefit to using 3rd party DNS in NZ, and why in fact it almost always makes your experience worse.

Cheers - N

The free filtering services opendns offers is the only reason I use opendns ...will do a serch though cheers.

blakamin

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#515930 2-Sep-2011 20:33

Talkiet:
Do a search on here for the number of posts outlining why there's no benefit to using 3rd party DNS in NZ, and why in fact it almost always makes your experience worse.

Cheers - N

QFT!
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Search GZ for this.

Talkiet

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#515933 2-Sep-2011 20:36

FreddyK:
Talkiet:
TheGreyPilgrim: Have had trouble this evening (ie broken internets!) using OpenDNS. Changing to Slingshot's own DNS servers or Google's DNS works fine. OpenDNS don't list any issues and I can use them no problem via a VPN, so what's up at Slingshot with accessing OpenDNS?

Do a search on here for the number of posts outlining why there's no benefit to using 3rd party DNS in NZ, and why in fact it almost always makes your experience worse.

Cheers - N

The free filtering services opendns offers is the only reason I use opendns ...will do a serch though cheers.

Well, that's actually a legit reason you have there :-) It's worth understanding the other performance implications though - check out both sides of the story - you may well be using the most appropriate solution.

Cheers - N

Please note all comments are from my own brain and don't necessarily represent the position or opinions of my employer, previous employers, colleagues, friends or pets.

TheGreyPilgrim

12 posts

Geek

#515936 2-Sep-2011 20:41

Talkiet: Do a search on here for the number of posts outlining why there's no benefit to using 3rd party DNS in NZ, and why in fact it almost always makes your experience worse.

Cheers - N

Like FreddyK I use them mainly for the filtering options to prevent my kids stumbling on questionable sites. I also like the fact they've been proactive (and first/only in some cases) in protection against some DNS flaws/exploits in the past. That said I'm interested in what others say re performance...

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sbiddle

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#516006 3-Sep-2011 00:31

TheGreyPilgrim:
Talkiet: Do a search on here for the number of posts outlining why there's no benefit to using 3rd party DNS in NZ, and why in fact it almost always makes your experience worse.

Cheers - N

Like FreddyK I use them mainly for the filtering options to prevent my kids stumbling on questionable sites. I also like the fact they've been proactive (and first/only in some cases) in protection against some DNS flaws/exploits in the past. That said I'm interested in what others say re performance...

Using a 3rd party DNS sever such as Google or OpenDNS will break every major CDN and deliver sub optimal internet performance for sites such as YouTube and Akamai where a significant % of major internet content is served from, and will also result in sluggish browing due to the high latency for every DNS lookup. If you believe the benefits of the 3rd party DNS outweight the massive hit in internet performance then feel free to use them. If you want optimal internet performance then stick with your ISP's DNS servers as these are your best bet.

TheGreyPilgrim

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#516028 3-Sep-2011 08:00

sbiddle:
Using a 3rd party DNS sever such as Google or OpenDNS will break every major CDN and deliver sub optimal internet performance for sites such as YouTube and Akamai where a significant % of major internet content is served from, and will also result in sluggish browing due to the high latency for every DNS lookup. If you believe the benefits of the 3rd party DNS outweight the massive hit in internet performance then feel free to use them. If you want optimal internet performance then stick with your ISP's DNS servers as these are your best bet.

Until I saw the Google/OpenDNS "Global Internet Speedup" initiative (afasterinternet.com) this week I never really considered CDN issues. Well duh, don't I feel stupid! I always assumed DNS servers were location aware and would give you the closest CDN IP based my location and not the DNS location - do none of them do that? ie is this initiative the first to solve this problem? (I can't believe this hasn't been thought of or addressed before now...!)

As for latency for basic website browsing (ie non CDN stuff), I've run GRC's DNS Benchmark in the past (should do it again actually) and I think that's a non-issue compared to other factors that might come into play - ie it's a tiny hit to take at the start of a connection, which can be far outweighed by a slow web server or bad javascript on a page for example.

So a related question to my initial post re Slingshot/OpenDNS, are there any ISP's that restrict specific DNS use? I imagine some might only let their own customers use their own DNS, but does anyone block 3rd party DNS?

sbiddle

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#516032 3-Sep-2011 08:26

While I don't personally know of any ISP's that restict access to 3rd party DNS servers, there does exist a good business case for an ISP to force redirects so that the use of 3rd party DNS servers was bypassed and all DNS requests went through their own DNS servers.

To use an example if you're an ISP offering unlimited YouTube and have a Google cache installed, somebody running a 3rd party DNS server such as OpenDNS will typically see their YouTube traffic will originate from the USA, meaning that the end user is not being zero rated for this traffic and will obviously then start saying the ISP is ripping them of. if the ISP redirected all DNS traffic to their own servers this wou;dn't be able to occur.

BlakJak

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#516057 3-Sep-2011 09:42

TheGreyPilgrim:
sbiddle:
Using a 3rd party DNS sever such as Google or OpenDNS will break every major CDN and deliver sub optimal internet performance for sites such as YouTube and Akamai where a significant % of major internet content is served from, and will also result in sluggish browing due to the high latency for every DNS lookup.?If you believe the benefits of the 3rd party DNS outweight the massive hit in internet performance then feel free to use them. If you want optimal internet performance then stick with your ISP's DNS servers as these are your best bet.

Until I saw the Google/OpenDNS "Global Internet Speedup" initiative (afasterinternet.com) this week I never really considered CDN issues. Well duh, don't I feel stupid! I always assumed DNS servers were location aware and would give you the closest CDN IP based my location and not the DNS location - do none of them do that? ie is this initiative the first to solve this problem? (I can't believe this hasn't been thought of or addressed before now...!)

As for latency for basic website browsing (ie non CDN stuff), I've run GRC's DNS Benchmark in the past (should do it again actually) and I think that's a non-issue compared to other factors that might come into play - ie it's a tiny hit to take at the start of a connection, which can be far outweighed by a slow web server or bad javascript on a page for example.

So a related question to my initial post re Slingshot/OpenDNS, are there any ISP's that restrict specific DNS use? I imagine some might only let their own customers use their own DNS, but does anyone block 3rd party DNS?

If you havn't already, read http://www.geekzone.co.nz/freitasm/6980

Then read http://www.geekzone.co.nz/forums.asp?forumid=95&topicid=89241&page_no=3#514874

Several ISPs have restricted external access to their DNS servers recursively - this was done a couple of years back in response to a vulnerability in DNS and particularly BIND (a popular DNS server) to reduce the threat footprint.
Prior to this it was quite common for resolvers to provide recursive service (to answer queries regardless of where they came from or where they were destined for) but there are quite a few who now lock this down.

Orcon leap out as one of the most obvious.

(This is problematic for folks outside of Orcon trying to troubleshoot DNS related faults for Orcon users, among other things.)

Your query goes to your DNS server, whatever you have specified.
The DNS server serves its cached answer, if it exists, or it makes the onward queries on your behalf, as described in the second link above. If the query is received by a CDN from the US East Coast (for example), then the CDN is going to serve you up a response that suits someone in the US East Coast. Not NZ.

No signature to see here, move along...

freitasm

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#516063 3-Sep-2011 09:56

TheGreyPilgrim: Like FreddyK I use them mainly for the filtering options to prevent my kids stumbling on questionable sites.

Try http://explore.live.com/windows-live-family-safety for Parental Control then and stop messing with DNS...

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numfarr

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#516232 3-Sep-2011 21:00

sbiddle:Using a 3rd party DNS sever such as Google or OpenDNS will break every major CDN and deliver sub optimal internet performance for sites such as YouTube and Akamai where a significant % of major internet content is served from, and will also result in sluggish browing due to the high latency for every DNS lookup. If you believe the benefits of the 3rd party DNS outweight the massive hit in internet performance then feel free to use them.

This isn't a problem for some CDNs any more apparently: Google, OpenDNS deploy DNS tweak for faster browsing . I haven't been bothered by it here previously, but we don't use a lot of YouTube or whatever anyway.

freitasm

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#516267 3-Sep-2011 22:23

First that os non-official and non-standard. Second, Akamai is not part of it, so it doesn't help much...

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Talkiet

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#516269 3-Sep-2011 22:25

freitasm: First that os non-official and non-standard. Second, Akamai is not part of it, so it doesn't help much...

Thirdly, their DNS servers are still hundred of miilliseconds further away :-)

Cheers - N

Please note all comments are from my own brain and don't necessarily represent the position or opinions of my employer, previous employers, colleagues, friends or pets.

numfarr

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#516293 3-Sep-2011 23:31

freitasm: First that os non-official and non-standard. Second, Akamai is not part of it, so it doesn't help much...

It solves the YouTube problem apparently, so it helps a bit. Also if you like you can whitelist certain sites for ISP DNS resolution, e.g. using DD-WRT.

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