So, I don't think there is anything I can DIY about the issue I'm
having, but I'll ask anyway ;)
As of last Thursday my internet access has gone from a really solid
37Mbps down to unusable at times.
The problem is not that the router disconnects (it still sits there
happily thinking it's connected at 40Mbps), but that there are very
large delays even when simply browsing.
The main sites I'm using for testing are www.bbc.co.uk, www.fast.com,
All I'm doing in the test is trying to load a page. Sometimes nothing
happens and times out.
Using fast.com shows a range of values from 0 to 37Mbps. It can cycle
good and bad several times an hour, or just a couple of times a day.
Re-booting, or power cycling gets it working again. But maybe that's
just coincidental, as if you don't reset, it does seem to recover by itself.
I've done a quick tracert on the above addresses and when it works
everything is sub 10ms. When it's in a bad mood, then some hops are
I've replaced the router (twice), the microfilter, and this issue shows
up on wired and wireless devices.
The last call to my ISP said that they had identified a non-specific
fault and would send someone out. Is "non-specific" just their term for
"we don't know what's going on"?
So, what sort of error would cause these symptoms?
A line fault that is introducing a high burst error rate. Basically
blocking error free transfer for periods of time. The ISP need to get it
raised with openreach (assuming its FTTC, and not unbundled).
If you do a quiet line test (dial 17070, and select it from the voice
menu), does the line sound continuously clear?
Most likely is line noise from a tree rubbing the insulation off or a
junction box compromised by ingress of water followed by daily freeze
thaw action. There has been a spate of freeze induced ADSL failures
round here this week (it has been down to -8C overnight). Plenty of the
"waterproof" underground junction boxes are full of water :(
Opening a command window and trying ping google.com might shed some
light. My guess is either you get perfect response <20ms or you get
exponential backoff if the packets go missing. If it is a DNS fault then
you might find using the numeric IP address works reliably.
Likewise error statistics off your modem if it can be persuaded to
divulge them will show which direction things are going missing and how
many uncorrectable errors have occurred. Sometimes routers can be pretty
dumb and stay on a high sync speed with insane error rates when dropping
a few Mbps would give a stable link.
My EE ISP provided modem is quite happy to stay connected with "0.6dB
noise margin" and no data flow. It is literally dead in the water but
doesn't seem to know it. Must be very confusing for their customers. BT
ones seem even worse for hiding their error statistics in dark corners.
On Wed, 13 Dec 2017 08:53:41 +0000, Martin Brown wrote:
One in our line somewhere, could tell when the air temp was getting
to 0 C as there would be a couple of ADSL2+(*) retrains. It's been
stable for the last 4 days but then the temp hasn't been above
freezing until midday yesterday...
Might be but more often than not these days sites are served from
multiple shared IPs so without the proper URL the server doesn't know
what to serve.
Some have them buried in the web interafce but more likely to need to
telnet or ssh into a command line interface.
(*) Been able to move from 20CN ADSL2 (up to 8 Mbps) to ADSL2+ 21CN
WBC (up to 24 mbps) not that it's made any noticeable difference to
the speed. It might have gone up 1 Mbps to 6 Mbps, what is noticeable
is the 30 second plus retrain period over the 8 of ADSL2.
Could be that your web access is running via a proxy service
(transparent or otherwise) and the latency problem lies there rather
than with your internet connection. Try some non-http speed tests, or
explicitly setting a different proxy.
Which ISP, Grumps? I have a similar problem with BT and the Homehub 6
router. The time-outs specifically led me to look at DNS problems, and
changing Windows (you can't change the BT router) to use Google's DNS
servers solved the problem. Extensive chats with BT and even them sending a
new(?) replacement router found no clue, other than an indeterminate fault
on the line which some of their operatives said was there and some of them
said was not there - i.e. they had no idea. I still have no idea what the
problem was (those more technical than me suggested it was a
hardware/firmware problem) but have got round it completely by changing all
my devices to use Google's DNS servers.
I don't know if you would want to change just as a test, but providing you
make a note of what you change beforehand, you can easily put it back. If
your router will let you change its DNS settings it's easier, of course,
change them in the router and you only need to make one change for
everything connected - I had to do each device separately.
The alternative - for me - with BT (which offers a good service otherwise)
is to buy a router which is better and more configurable but as you have
access to more than one router maybe one of them can be reprogrammed to
Google's (or others - there are a few good servers about) settings to test
Now that was interesting. Despite having had Plusnet FTTC for the last
year, I’ve never felt that general web browsing has been anywhere near as
fast as it ought to have been.
My Technicolour router doesn’t seem to allow DNS changes but via this site
I was able to change the LAN private settings to the google DNS settings.
Now I have no idea what all this means but web pages are loading a heck of
a lot faster now. If I look at my basic internet setting though, the
original DNS setting seem unchanged but as long as my browsing is way
faster, I don’t care!
I'm not sure what you mean by changing the LAN settings or where you
changed them - but if you mean within Windows/Android/whatever then you are
doing what I did by overriding the DNS settings locked into the router.
That, if we had the same problem, could certainly result in big speed
increases. Google's DNS servers are quick and you've removed a major
bottleneck to the pages you browse.
I still can't work out why I (and many others) have this problem with
BT/Plusnet's servers, because if there was something wrong with the actual
remote servers they would have tens (hundreds?) of thousands of complaints
(I assume they don't?) about it - but, like you, so long as everything is
faster I don't care a tinkers cuss. I changed mine months back now and the
actual line speed remains much faster (the actual connect speed was always
fast), so I've given up trying to get any sense out of them.
On Wed, 13 Dec 2017 15:16:32 +0000, Bob Henson wrote:
Plusnet said this (in reply to Tim, but probably worth a wider audience):
What you're seeing is less likely due to Google's servers being more
responsive than ours, and more likely the result of you removing the
router's DNS proxy from the equation when performing lookups.
i.e. before, you were doing this for each lookup:
client device > router > plusnet DNS resolver
Now, because you've told the router to assign Google's DNS to each client
directly (rather than have proxy requests through the router),
you're doing this:
client device > google DNS resolver
You'll probably find you have equal success assigning two of Plusnet's
resolvers in the same way:
220.127.116.11 18.104.22.168 22.214.171.124 126.96.36.199
So it becomes:
client device > plusnet DNS resolver
Our DNS servers are without a doubt physically closer to you than Google's
(from a routing perspective).
As an aside, you *can* change the DNS settings used by the router,
however it needs to be done using telnet and the CLI -
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £1 a message.
Very interesting, and refreshing to know that at least PlusNet admit the
problem can and does happen - more than their parent BT does. It would be
interesting to try doing what they suggest just to see if it does also
solve the problem. I may do so, even though I have worked round it myself.
However, "worked round" isn't good enough - surely someone at BT should
have been interested in solving the problem?
When I first got my BT router with its included DNS settings all was well
for a couple of months. One day it suddenly refused to connect to a website
at all occasionally and timed out on many/most connections - seeming at
random. It instantly recovered when I changed, after considerable research,
to Google's DNS servers - so there was no doubt in which general area the
No-one that I could find at BT could suggest any solution at all - most of
them had little or no idea what I was talking about or pretended not to do
so. The very first one was downright rude. It's hard to imagine how people
so dim and inarticulate could be in customer service at all. It would have
helped if they spoke reasonable English too. If they had made the
suggestion that Plusnet (BT) made, I would have tried it immediately,
albeit the extra stage had never been a problem before and it would still
have provided no explanation.
Instead, they all told me nothing was wrong - presumably they thought I was
hallucinating. One eventually sent me a new router - I thought that might
help as it seemed to me it was a hardware and/or firmware issue. It didn't.
I've since spoken to lots of folk online and off who are much more
technically qualified then I am, but still no-one has an explanation.
I've just read the whole of the thread from which you quoted and it does
appear to give a partial answer to my question. The answer would appear to
be the one I really didn't think possible with an organisation of that size
and importance - BT's DNS server system is totally crap. Luckily, my
suggested possible solution to Grumps was still correct - from what I
considered to be my position of relative ignorance. However, it would
appear that I am far better informed than BT's customer service staff.
I did ask and was told that it was impossible - but I wonder if it might be
worth my while trying again to prise the information how to change my BT
Homehub 6 router's DNS servers out of them? Not a snowball's chance in
Hell, I suspect. Thanks for aiming me at that thread, anyway.
You can always override the DNS servers used on your computer anyway by
specifying them in the configuration of your network adaptor, rather
than using what the router hands out via DHCP.
(some routers pass on the actual DNS server addresses they are
configured with, others will pass their own address and then act as a proxy)
Given the time of year, one possibility is RF interference from some
dodgy Christmas lights.
Did you or a neighbour turn on some Christmas lights last Thursday?
Thanks all for your suggestions.
It's too difficult replying to all as the line is up and down like a ...
The ISP is Sky.
It's one of their fibre products, with copper to the house.
The line test says that there is a little echo but no noise.
The cables are all underground so no trees rubbing etc.
Could be water in the cable, who knows.
There are no local wacky Xmas lights.
I have a man coming round on Sunday. Likely he'll have no clue, but I'll
keep you posted.
Just if anyone is interested...
The Sky/OpenReach engineer did NOT turn up, so none the wiser about the
"non specific" fault they detected.
But the problem turned out to be a laptop with a new install of OneDrive
which was hogging the router during its initial sync.
Has been sorted by setting max upload/download limits within OneDrive
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