Regular DNS Not Responding & Speed issues.

[#1]

Hi.
Sorry bother you folks, but I've come to pick some brains.
I've been experiencing a considerable number of disconnections recently and it doesn't matter whether I use wireless or wired connections, the problem is the same and I know this because when I've used Windows 7 internet troubleshooter it comes up with "The DNS server is not responding".
Now this can last just 10s, sometimes it's a lot longer and it sometimes requires a reboot of the router (Draytek 2850n) or computer to resolve the issue, is there an alternative to this and if so how do I do it?
I know about putting alternatives into the properties box when you access either the USB adaptor (N65 USB Adaptor) or onboard Gigabit adaptor for the wired connection and insert alternatives in there. Not that it seems to make a jot of difference.
Also my line speed has dropped by over 10 meg, because at one stage I was regularly getting 65-69 Mbps, now it's an average of 50-55 Mpbs, sometimes it drops below 50, OK that's still fast, but not overly happy about a drop like that.
Any ideas on how to resolve these issues would be appreciated.

[#2]

We aren't seeing any drops on our end and the ones that are there I'm guessing are when you reboot your router?

Your actual sync speed hasn't changed either. That's at 74mbps so your throughput shouldn't be as low as what your seeing.
Do other devices have the same issue?

[#3]

Have you checked the routers log for dropped connection?
A dropped VDSL connection can be up again before the ppp session times out, in which case it probably wouldn't show on PN's graph.

[#4]

It's just happened again now twice.
It may show that I rebooted the router as well, which is correct I did, I have also inserted the DNS Server to be used as Open DNS-2:  208.67.222.222 to see if that will make any difference to reliability & performance.
I know something is wrong as Google is freezing quite readily and Google Maps doesn't appear complete. Also some pages are slow to load up.
As for the Draytek log, I haven't got a clue where to look! It's so darn complicated to use. I can't use the BT modem & Technicolor set up, I haven't got enough power sockets to do it! 

[#5]

There was just a random burst of connections that haven't showed up before.
About 18 in the space of 4 minutes.
It'll be hard to tell if its a line issue without trying the Openreach modem and Technicolor as a alternative.
Is there no way you can attach a four plug extension to the one power socket that's there?

[#6]

I'm already on a 6 gang socket and they're all in use! 

[#7]

You could run a TBB quality monitor / ping graph.
http://www.thinkbroadband.com/ping
That will give a indication of any dropped connection.
But you really need to do as Mathew says and try the BT modem and Plusnet router. It's plusnet who you need to convince there's a problem before you can get it investigated.

[#8]

How can I when I haven't got any power sockets left?  
As you can see the line speed has dropped again down to 51, I have tested it again since and it's dropped again to 37!
I've had the DNS error occur at the following times:
21/02/15: 1256
22/02/15: 1504-1507, 1545-1546, 1604-1605,1645-1647
And if you have a look at the attachment you'll see that the BT Speedtester concurs with my speed drop & now says to report the issue.

[#9]

Right as an update, I've daisy chained a couple of extension leads together (Not happy about that) but as a temporary measure, it'll do, however!
It has taken me over 45 minutes to connect and I can only do so wirelessly, I cannot connect using a cable at all. So it looks like I have a duff Technicolor router as well, so the whole lot will be disconnected and boxed back up! VERY UNHAPPY!
Oh as soon as it did connect, it came up with the same DNS failure!  
Update
This bit has been added via my old Draytek 2850n and via a wired connection, which I did to prove the cable connection wasn't broken & the Technicolor is broken.

[#10]

Quote from: Matthew

We aren't seeing any drops on our end and the ones that are there I'm guessing are when you reboot your router? Your actual sync speed hasn't changed either. That's at 74mbps so your throughput shouldn't be as low as what your seeing. Do other devices have the same issue?

I'm getting a general slow down, I've checked my router and for some reason in the log it reverted to "Training" when it comes to the line speed. Odd.
I've lost DNS again another twice tonight at 2020 - 2025 & 2108 - 2109. No connection to the net and a yellow triangle with exclamation mark on the internet connection icon on the taskbar. Getting really cheesed off now.

[#11]

I'm guessing you're problem is dropping the vdsl connection as I explained in the above post.
The DNS issue is a red herring, if the internet is down there's no DNS!
Plusnet's graph is not showing any dropped connection so you need to find a way to prove if this is whats happening before you can expect PN to arrange a BT visit.
Look again for a router log file and think about a TBB ping graph.

[#12]

Well it's just done it again and whilst I was in the router menu and it alerted me without any warning that the connection was lost as there was a network change.  
What the hell is going on?
I take it TBB is thinkbroadband?  If so I've set one up, but that'll be days before anything is shown. I'm really starting to think about paying the £80 or so to quit and go to BT or VM instead.

[#13]

Does anyone know why my linespeed profile has now been cut from 74Mbps to 60Mbps?
Last speed test was showing a pathetic 35 Mbps. 

[#14]

Nice to see the complete lack of interest by Plusnet customer services.
I've found that my IP address has changed several times without my intervention, my connection speed has once again collapsed into the 30 Mbps territory.
VERY UNHAPPY INDEED!

[#15]

Sorry to see this hasn't been picked up yet.
Our testing is showing a external issue so I'm just raising this to our suppliers now.