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Web Browsers Not Connecting to Internet - DNS Problem?

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Community Star

Here is another bit of info that may be of use

 

Cannot load websites after updating Firefox
If you were able to load websites until you updated Firefox, your Internet security software (including firewalls, antivirus programs, anti-spyware programs, and more) is likely preventing Firefox from connecting to the Internet. Some Internet security programs can block Internet access even when they are in a "disabled" state.

In general, you should remove Firefox from your program's list of trusted or recognized programs, then add it back. For instructions on how to configure these programs, see the Configure firewalls so that Firefox can access the Internet article.

Firefox connection settings
If you connect to the Internet through a proxy server that is having connection problems, you will not be able to load websites. To check your connection settings in Firefox:

Click the menu button Fx57Menu and select Options.
Select the General panel.
Scroll down to Network Proxy and click Settings....
Change your proxy settings:
If you don't connect to the Internet through a proxy (or don't know whether you connect through a proxy), select No Proxy.
If you connect to the Internet through a proxy, compare Firefox's settings to another browser's (such as Internet Explorer - see Microsoft's guide to proxy settings).
Click OK to close the Connection Settings window.
Close the about:preferences page. Any changes you've made will automatically be saved.
DNS Prefetching
DNS Prefetching is a technique Firefox uses to speed up loading new websites. To disable DNS Prefetching:

Type about:config in the address bar and press Enter.
A warning page may appear. Click Accept the Risk and Continue to continue to the about:config page.
In the Search field at the top of the page, enter network.dns.disablePrefetch.
If the preference does not already exist, select Boolean and click the Add Fx71aboutconfig-AddButton button to create the preference.
Change the preference value from false to true by pressing the Toggle Fx71aboutconfig-ToggleButton button.
IPv6
Firefox supports IPv6 by default, which may cause connection problems on certain systems. To disable IPv6 in Firefox:

Type about:config in the address bar and press Enter.
A warning page may appear. Click Accept the Risk and Continue to continue to the about:config page.
In the Search field, enter network.dns.disableIPv6
In the list of preferences, click the Toggle Fx71aboutconfig-ToggleButton button next to network.dns.disableIPv6 to change its value from false to true.

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Team Player

Hello,

 

Thanks for the Firefox advice. I temporarily disabled the AVG shields to see whether that helped but it

didn't. I left Firefox on No Proxy as it was working previously like this. I toggled the Disable DNS

Prefetch and Disable IPv6 to true and, after a reboot (required by AVG to restore its shields), Firefox

loads pages. Unfortunately, Opera has now reverted to not loading pages!

 

Another reboot. AVG shields are still operative. I load Opera and find it is now working OK but then

load Firefox to find it has swopped places and is not loading. Something weird is going on.

 

Ah! AVG now pops up a warning (even though I didn't tell it to do anything): "Something's blocking our

scan...a potentially malicious piece of code is getting in our way". I click "Resolve Now". It says

"Resolving access rights" - the busy circle goes round, and round... Eventually, I get tired and close

the pop up. It doesn't appear to doing any scanning.

 

I don't know whether this is a bug to be ignored or something more sinister. I guess I need to do virus,

malware and rootkit scanning to be on the safe side.

 

Can you make head or tail of all this?

 

GeorgeTT

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Community Star

Try running this free online scanner from f-secure.

The same company that supplies TalkTalk's home safe virus / firewall software

follow this link and let it scan your system.  Try to run it from microsoft IE

 

https://www.f-secure.com/gb-en/home/free-tools/online-scanner

 

Now the mad question.  Have you tried all this from another account on the system you use.?

To me it sounds like you have picked up malware program that is re-directing your browsers.

Plus make sure VPN is turned off in Opera.  I use both Opera and Firefox.

 

 

Highlighted
Team Player

Sorry. Couldn't get it to run in IE7 (even though it loads other sites). Tried in K-Meleon. It says "This version of Windows is not supported".

I can try AVG scan. Also, have Malwarebytes and Spybot. Do you want to suggest something else?

 

The Opera version 36 doesn't have VPN and I'm not using a stand-alone VPN.

 

I have only the one account. It's not something I ever thought of altering.

 

GeorgeTT

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Community Star

You can run that f-secure link from any working browser.  It's a remote virus and malware checker

When i said another account i meant create another admin user on your pc system system. Logon to that created user and try run  from that account the f-secure remote checker via link i sent.

 

Highlighted
Team Player

Yes, I am trying to run it in the browsers but without luck. IE is working but will not load this

webpage; Opera (just loaded) has reverted to "DNS address could not be found"; Firefox (also just

loaded) says "can't find the server at www.f-secure.com".

 

The page loads in K-Meleon and the Run Now button give you the f-secureonlinescanner.exe file to

download and run. When it is run it says "This version of Windows is not supported". In view of this, I

don't think it is necessary to try it again by setting up another user account in Vista, unless it would

be useful for checking the browser DNS problem. I'm not familiar with what difference it would make to

have a different user account (an aspect of computer use I have never looked into).

 

I have this morning run the AVG Boot time scanner which found nothing amiss. Also, ran the AVG virus

checker on the system drive with no problems found. These scans include rootkit checking.

Next, ran Malwarebytes - no threats found. Finally, ran Spybot which found a large number of Unknown ADS

instances (files, domains, cookies) but, from what I understand, this does not indicate they are

rootkits/malware; short of examining each instance and knowing what to look for, I don't know how easy

it would be to determine whether they are infected.

 

As both Opera and Firefox are now not working, I'll reboot to see whether that fixes it for both or

either of them. ... Rebooted - no difference. This is getting tiresome!

 

OK, I'll try removing some programmes from the startup procedure: Spybot, Malwarebytes, Outpost now not

set to start at boot-up; can't set AVG not to run at boot-up so left it. ... Rebooted again and Opera is now

loading pages but Firefox is not.

 

I don't know whether that means one of those programmes is at fault or, perhaps, this is just

coincidence. Anyway, I'll leave it for now but later I will try adding them back (one at a time) to run

at boot-up and see if that causes trouble.

 

GeorgeTT

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Community Star

I'm not an expert, but surely it is no surprise that the file will not run with such an old operating system. And IE7, honestly? 

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Community Star

Ok. Not really much more i can say. Too many restrictions with Vista

If you have a cd / dvd try create a bootable cd /dvd from one of the following progs

 

https://www.lifewire.com/free-bootable-antivirus-tools-2625785

 

Unless anyone else has any suggestions then i am been stone walled.

 

Highlighted
Team Player

Hello ferguson and paulshent,

 

Fair enough. Having tried all the suggestions you and FritzCT have kindly made, I guessed this was as good as it was likely to get. At least I have Opera working and that is normally the only browser I use these days, with Firefox as a back-up. I never took to IE because of all the security warnings that were being made about it. It still seems a bit precarious as to whether Opera will continue working and I'm not sure any of us can quite pinpoint what it was that caused the problem in the first place, so I shall just have to hope it keeps going.

 

I'll try using the free anti-virus tools paulshent has suggested and see what they find. As the checks I have already made don't show anything obviously sinister, I not sure it is a virus/malware caused problem, but we shall see.

 

Regarding the router logs, I have made some checks with past posts on the Forum and found some information that explains much of what I was concerned about. In fact, only last Saturday someone posted about the every-10 minutes Intrusion warnings and was reassured by KeithFrench that his router was simply indicating that they had been blocked. It did occur to me to ask what happens to intrusions that are not blocked - how would someone know that an intrusion had succeeded? I wonder if this is so widespread that people only know of it if and when they have occassion to look at a router log. Anyway, I may open a thread on this matter if I can't find all I want to know from other posts on the Forum.

 

So, many thanks for all the time and effort you have all put in to offering advice. If anything further occurs to you that might be helpful, please do post it and, if I get stuck again, I can always ask for more help.

 

GeorgeTT

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Problem Solver

Hey guys

 

Apologies but I've been working.

 

I'm still not convinced this is a malware issue but more likely a networking or hardware one. Maybe a wrong setting somewhere, the rouer giving up, internal wiring, external wiring, that kind of thing. Did someone suggest /scannow? I seem to recall they did and if so how did that work out. This might be something that @KeithFrench can offer some perspective on.

 

Anyway if you want to rule out the possiblity of malware your best bet might be to try the Malwarebytes forum. They have some seriously good analysts there that will have a real close look at log files to pick up any hint of malware that even the scanners don't report.

 

Fritz

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Community Star

Hi @GeorgeTT 

 

Before I could offer help on this, it is a long thread with help from some very knowledgeable people. It would take me ages to read through all of this. Perhaps you could summarise where you are with it currently?

Keith
I am not employed by TalkTalk, I'm just a customer. If my post has fixed the issue, please mark it as the Best Answer.
OCE's and Community Stars - Who are they? 

Highlighted
Team Player

Hello Keith,

 

Thanks for joining the thread. It is quite a complicated story but I'll try to tell it briefly.

I use Windows Vista, Opera v.36, Firefox v.52.9. A week ago, Opera stopped loading pages showing a "DNS address could not be found" error. Firefox also stopped with a "Firefox can't find the server" error. I already had K-Meleon installed and found that did work without trouble (and has done throughout this week) and so was able to post on the Forum. I've found IE7 also works. I normally only use Opera and

would like to keep using it.

 

I've done a factory reset on the HG633 Router, checked the Proxy settings and DNS settings in the browsers, flushed the DNS - all as suggested by paulshent and FritzCT. At various points, Opera and Firefox have started working properly only to revert to the problem after Opera crashed or after rebooting Vista.

 

I've also tried removing start-up programmes temporarily - Outpost firewall, Avast anti-virus (since removed and replaced by AVG), Malwarebytes and Spybot, to see whether they might be a cause of the problem, but with mixed results - at one point, after removing Avast, Firefox worked but Opera did not then, after installing AVG, Opera worked but Firefox did not!


Malware, rootkit and virus checks by the mentioned programmes have not shown anything sinister (though Spybot found a large number of Unknown ADS instances).

 

The current situation is that Outpost firewall and AVG anti-virus are run at start-up; Opera is working fine but Firefox will not load any pages. Given that Opera has reverted to not loading pages after a crash and after a reboot, it may only be time before the problem reappears, so knowing what is actually causing this would be useful to fix it once and for all.

 

Does this give any clue to the problem? I would be grateful for any insight you can offer.

 

GeorgeTT

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Community Star

The only thing I can think of as it works on some browsers & not others, is it due to increased security measures in Firefox & Opera. Have you tried numerous sites in these two browsers & do they all get the same error?

Keith
I am not employed by TalkTalk, I'm just a customer. If my post has fixed the issue, please mark it as the Best Answer.
OCE's and Community Stars - Who are they? 

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Team Player

Hello Keith,

 

When the problem starts, I have tried to access various sites (such as eBay, Amazon, IMDB, TalkTalk) but none will load as it always gives the error message. As I said, the browsers have at various points this week started working properly and had no trouble accessing those and other sites. I can't discern any obvious reason as to why they stop and start.

 

Before this started, I had not made any alterations to the settings in Opera or Firefox. Do you know what setting in particular would affect the browsers in this way?

 

GeorgeTT

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Community Star

I assume ( as you mention Amazon) these are https sites & not http?

 

What I would do if it was my PC is to a Wireshark trace of the problem to see what is going wrong. I can help you get a trace & analyse it for you.

Keith
I am not employed by TalkTalk, I'm just a customer. If my post has fixed the issue, please mark it as the Best Answer.
OCE's and Community Stars - Who are they? 

Highlighted
Team Player

I hadn't thought of checking that. I've had a look at Opera and find there are a mixture of http and https sites loading. In Firefox, I've tried both and find that none will load - "Server not found".

 

What would Wireshark show? I can give it a try.

 

GeorgeTT

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Community Star

Wireshark will show you every single IP packet passing your network adapter in great detail, it is not a tool for the faint-hearted.

Keith
I am not employed by TalkTalk, I'm just a customer. If my post has fixed the issue, please mark it as the Best Answer.
OCE's and Community Stars - Who are they? 

Highlighted
Team Player

OK. I will take a look at it later this evening. I have never used it so would appreciate a few tips on how to set it up to do what we want. I believe it can process a lot of different data but I guess we only need certain things to try and diagnose this particular problem. Thanks.

 

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Community Star

I will PM you a guide on using this later today.

Keith
I am not employed by TalkTalk, I'm just a customer. If my post has fixed the issue, please mark it as the Best Answer.
OCE's and Community Stars - Who are they?