Tracert's to ntp.plus.net
Quote from: Bob I think BGP or something similar is used to route you to the closest cluster which is the basis for the question jelv asked
Thanks for the explanation Bob, it all sounds very good and from this you would expect the plusnet name servers to be the fastest around for PN users. Unfortunately my tests using DNS Benchmark frequently show PN's name servers to be the slowest for cached look ups.
Is there a reason for this and is there any plans to improve?
Quote from: Bob The IP's you see in traceroutes are not those of the physical caching DNS servers themselves. They are virtual IP's. The physical caching servers themselves are clustered across two sites for resiliency.
Bob,
Thank you for the clear explanation which has not been so well given in previous discussions on this topic.
Quote from: Bob I'm going to bow out now before I get out of my depth, however if this thread is a question of whether or not we've sufficient network redundancy then I don't think people have anything to worry about
...and take the rest of us with you. I suggest that the questions have arisen out of numerous recent issues where DNS name resolution has repeatedly failed completely or in part or (as noted by NPR) not been particularly fast.
On that subject I'm sat at home ( rather than on my business site ) and am finding some issues with DNS resolution... but that might be related to the connectivity issues I'm waiting for BTOR to come and investigate.
Kevin
Quote from: townman
On that subject I'm sat at home ( rather than on my business site ) and am finding some issues with DNS resolution... but that might be related to the connectivity issues I'm waiting for BTOR to come and investigate.
Kevin
Could run your own caching DNS resolver, I gave up on all ISP DNS resolvers years ago.
I can recommend Unbound DNS, very easy to install and been 100% reliable during the years I've run it.
Details in the usual place
Quote from: Anotherone So in the example I quoted about xe-10-0-0.ptw-cr01.plus.net falling over, what you seem to be saying is it has sufficient resiliency built in making is less likely to fall over completely, but should it do so, somehow (beyond your knowledge), it would go to another physical unit cr02, if I've understood that correctly.
Yes, you've understood correctly
Quote from: Anotherone Which is fine, but I suppose the underlying query, which none of this answers is why many of us see random periodic fails in DNS lookups.
Do you?
I certainly wasn't aware of any widespread complaints and I've not personally noticed any problems myself. Whilst other servers might be quicker responding, ours should rarely fail unless there's a service wide problem of some description.
Quote from: npr
Quote from: Bob I think BGP or something similar is used to route you to the closest cluster which is the basis for the question jelv asked
Thanks for the explanation Bob, it all sounds very good and from this you would expect the plusnet name servers to be the fastest around for PN users. Unfortunately my tests using DNS Benchmark frequently show PN's name servers to be the slowest for cached look ups.
Is there a reason for this and is there any plans to improve?
That's the slowest of the fastest percentile though I'm guessing? I very much doubt our servers are slower to respond than the majority of publicly accessible resolvers. Using a default namebench install I get the following which shows our resolvers to be up there with the quickest of them.
I've just downloaded and optimised DNS Benchmark too. Out of thousands of resolvers it claims to have selected the fastest 50 or so. Granted if I specify our server address by comparison then it doesn't look good but Google doesn't seem to fair much better either. Both are in the bottom five:
Location isn't everything and there are clearly other factors that need considering. The architecture of the physical boxes themselves and the software being used etc. Whilst the round trip time to our caches should definitely be quicker than to other DNS servers, that doesn't guarantee the quickest average DNS response time.
In summary, our caching DNS servers should be perfectly fine to use. There are reasons you may want to specify others though e.g. for resiliency and if you roam (I think our servers are locked to our IP ranges). You might even want to replace your primary server with a non-Plusnet server. Personally though I don't think the milliseconds it purportedly saves makes much of a difference
To answer your other question, I don't think there are any immediate plans to overhaul the DNS platform.
Quote from: Bob
Quote from: Anotherone Which is fine, but I suppose the underlying query, which none of this answers is why many of us see random periodic fails in DNS lookups.
Do you?
I certainly wasn't aware of any widespread complaints and I've not personally noticed any problems myself. Whilst other servers might be quicker responding, ours should rarely fail unless there's a service wide problem of some description.
I'm not referring specifically to anything that's just cropped up. There have been many threads over lengthy periods, where we've experienced these things, and you have responded to some of them IIRC. Using an alternative DNS server always remedies the problem, so it's difficult to draw any other conclusion, however I am (as always) prepared to be educated on these things
Quote from: Bob
That's the slowest of the fastest percentile though I'm guessing? I
You could put it that way
IMO PN's servers should easily be the fastest for cached look up, they have the home advantage.
I can ping ntp.plus.net in under 16ms yet PN's cached name look ups takes on average 30 to 40 ms -- there's a lot of time being lost somewhere.
Quote "In summary, our caching DNS servers should be perfectly fine to use."
I don't doubt that, I'm just questioning whether they should / could be faster.
