2015.10.2.2214 web shield blocks DNS

Avast Free Antivirus / Premium Security
1

On one PC, the 2015.10.2.2214 update of Avast Free Antivirus blocked DNS. Windows 7 SP1 32-bit claims no Internet access and nslookup times out. There is nothing wrong with the DNS configuration or servers. Switching off web shield makes DNS work. Even with the web shield on, it is possible to access web sites via IP address, and it’s possible to tracert -d to the DNS server. I tried using Google’s 8.8.8.8 and 8.8.4.4, which are certainly legitimate DNS servers.

It was interesting that after the update I did not get the Google Chrome offer dialog. Uninstalling, running avastclear and reinstalling with default settings does not help. After a reinstall, I couldn’t uninstall normally, because it said the installer is running. I had to reboot into safe mode to uninstall. I wonder if something is going wrong at the end of the installation process. Going back to 2015.10.0.2208 fixes the problem.

That PC has absolutely nothing else installed besides Windows 7, SP1, drivers and Avast. The firewall is configured for a public network. Maybe some of this is triggering a bug?

Is there an Avast feature relating to DNS which can be disabled? I read that Secure DNS was introduced recently, but that’s apparently not available in the free version, and I see no setting for turning it off.

2

It’s been reported multiple times in the past month. There’s something wrong with how Avast is handling DNS. No fix available.

3

Have you tried flushing your DNS?.

Windows Vista / Windows 7 Flush DNS Due to MS security you must run the command prompt with administrator privileges.

  1. Click the start button and navigate to the command prompt (Start > All Programs > Accessories > Command Prompt)
  2. Make sure that you right click on the command prompt application and choose “Run as Administrator”
  3. Type in the command ipconfig /flushdns
4

I’ve seen several systems that seem to be having similar symptoms with the latest Avast. I didn’t have permission to take a closer look, so I wasn’t able to do so.

5

Not limited to the “latest version”… it was like this in the previous version as well.

This is about the farthest its gone:

https://forum.avast.com/index.php?topic=166031.msg1182590#msg1182590

6

Since the User never replied, there really isn’t anything that can be determined.
I’ve never seen that problem but, we all run different OS, programs and are connected through different ISP’s.
If you have a problem, you need to be willing to follow through on having it resolved.
If your not, complaining really doesn’t accomplish anything.

7

Is there a point to your post? I have no idea why the person stopped responding, however just because he stopped, doesnt mean the other five people that started new threads in the lsst month dont have a problem. Not everyone is a software engineer so I personally dont know what more I could offer however if avast asked for info I would certainly provide it.

If avast were a bit more proactive in asking for logs or some other troubleshooting material then possibly they would fix things quicker however since there are still bugs that have been floating around for over a year, which they havent fixed, I dont really get the impression that will happen.