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Consumer Products => Avast Free Antivirus / Premium Security (legacy Pro Antivirus, Internet Security, Premier) => Topic started by: Popo on November 23, 2011, 08:40:51 AM

Title: Avast Network Shield Issue - loosing connection
Post by: Popo on November 23, 2011, 08:40:51 AM
Hi,


I have a new, clean install of WinXP SP3, and I use Avast Pro 6.0.1289 paid version. Problem is - with Network Shield active i can`t connect to any website (Firefox 8.0.1), but i can ping those websites with cmd/ping.

Additionally in windows log shows some DHCP 1000,1003 and 2505 errors. Only when Shield is active.

WinXP, Firefox and Avast are only 3 programs installed on my pc. I have checked other network cards, and it doesn`t change anything. When shield is deactivated everything works fine, but... what is the point of paying for program if you cant use all it`s features?

Peter
Title: Re: Avast Network Shield Issue - loosing connection
Post by: iyogisolutions1 on November 23, 2011, 09:12:08 AM
Hi,

Please change the settings in the Avast

          Web Shield"->"Expert Settings"->"Main Settings

Please enable "Scan traffic from well-known browser processes only "

Hope the issue will be fixed.


Title: Re: Avast Network Shield Issue - loosing connection
Post by: ady4um on November 23, 2011, 09:34:52 AM
@Popo,

Since you are reporting about Network Shield, and the above suggestion talks about Web shield, please report back if that suggestion was enough to solve your problem (it may).

In addition, are you using any firewall?
Title: Re: Avast Network Shield Issue - loosing connection
Post by: Popo on November 23, 2011, 10:23:47 AM
Sorry, my mistake - the issue is with Web Shield. I am using Polish version, and mistranslated it.

Unfortunately Yogi solution didn`t work.

I am using Windows Firewall. As i told you earlier - this is fresh system. (may be a little bit ancient - Celeron 2.2 Ghz + 512 mb ram, but that will be more than enough for office work)
Title: Re: Avast Network Shield Issue - loosing connection
Post by: ady4um on November 23, 2011, 10:07:02 PM
Do you currently have any other security tool installed? Or maybe you installed one and uninstalled it later?

In addition, do you have any rules in your firewall related to Avast?

Do you have this problem browsing to any url, or just on specific sites?

Please try with IE instead of FF, just to test if you can use it with the web shield being active.

Please report back.
Title: Re: Avast Network Shield Issue - loosing connection
Post by: DonZ63 on November 23, 2011, 11:21:01 PM
Sounds to be like a possible issue with Avast web shield localhost proxy and Firefox 8?

Perhaps someone using Firefox 8 can chime in. I don't use Firefox.
Title: Re: Avast Network Shield Issue - loosing connection
Post by: iyogisolutions1 on November 24, 2011, 12:05:02 AM
This can be also occur due to incorrect proxy settings in the web browser for Avast

Please try this work around,and update us back

 Include the Proxy server settings for Internet Explorer when using broadband and/or local area network (LAN) Internet connection
1.   Start Internet Explorer.
2.   Select Tools -> Internet Options... from the main menu.
3.   Switch to page Connections.
4.   Click on the LAN Settings... button.
5.   Check the option Use a proxy server for your LAN.
6.   Write localhost into the Address field (alternatively, you can enter IP address 127.0.0.1, which is the same as localhost).
7.   Enter 12080 into the Port field.
8.   Confirm with OK button
Title: Re: Avast Network Shield Issue - loosing connection
Post by: Popo on November 24, 2011, 07:58:37 AM
Hi guys, i really appreciate your help.

Ady4um - I don`t have any other security tools, and I didnt install any of them earlier on this pc.

iYogisolutions1 - Tried this, but i keep getting "connection rejected by proxy" error in FF, and general error in IE.

I am wondering, if by any chance that is a hardware problem. Avast works perfectly on 3 other pcs in my network, and this is first time I have ever had problem with it.

Best Regards
Piotr



Title: Re: Avast Network Shield Issue - loosing connection
Post by: lukor on November 24, 2011, 12:45:01 PM
Hi Popo,
how are you connected to the network? Do you have multiple network cards? DHCP error 1003 is displayed when there are more that one DHCP server on the network, which is probably a faulty configuration. Can you please check that?

Lukas.
Title: Re: Avast Network Shield Issue - loosing connection
Post by: Popo on November 24, 2011, 02:42:04 PM
Hi Lukor,

indeed I have 2 cards, but I installed second just to make sure, that first one was working as it should. Pc is connected directly to router in my office, and router is connected to rest of network in building. All other PCs use deafult settings and they work absolutely fine, without avast problems.

Best Regards
Piotr
Title: Re: Avast Network Shield Issue - loosing connection
Post by: lukor on November 24, 2011, 04:38:39 PM
So, to sum it up:

Your internet connection works OK, you can send emails, ping your local network, ping internet. However you are unable to browse in the Web browser (Firefox). The problems vanish as soon as you turn off the WebShield provider (Osłona WWW).

I am right? The same happens for Internet Explorer?

Could you please try to restart "Avast! Antivirus" service, from the services control panel. Any changes after that?
Title: Re: Avast Network Shield Issue - loosing connection
Post by: DonZ63 on November 24, 2011, 04:50:40 PM
Have you tried to reset the TCP/IP stack?

Open a command prompt window and type:

ipconfig /release

when that command completes, then type:

ipconfig /renew

Are the other PCs that connect OK using Avast connected to the same router?

Is the DHCP server you are connected to located on that router or does your company use a dedicated DHCP server?
Title: Re: Avast Network Shield Issue - loosing connection
Post by: Popo on November 25, 2011, 08:07:39 AM
DonZ64 - Reseting TCP/IP stack didn`t help. We use our own router as DHCP server. Other pc`s work fine.

Lukor - You are right. I can ping my network, connect to mapped drives, print stuff, etc. with Webshield on, but I can`t browse. It doesn`t matter if I use FF, or IE, it still doesn`t work. I am slowly running out of ideas.
Title: Re: Avast Network Shield Issue - loosing connection
Post by: ady4um on November 25, 2011, 03:51:50 PM
I wonder if the problem is only related to http traffic, or anything going through web browsers. I mean, if you open some "ftp://" site in IE...

I guess Lukor would be able to find what's going on with some more tests.
Title: Re: Avast Network Shield Issue - loosing connection
Post by: DonZ63 on November 25, 2011, 10:22:59 PM
Do have any other proxy servers on your PC or on the router? uTorrent, etc.

Can you connect to a https web site?

Another possibilty is Avast web shield is just not compatiable with your NIC. Or the NIC driver is partially hosed.

From the command prompt window type ipconfig /all and verify the DNS and DHCP servers are your gateway i.e. router. BTW - where is your DNS server? On the router?

Title: Re: Avast Network Shield Issue - loosing connection
Post by: DonZ63 on November 25, 2011, 11:11:48 PM
A few more ideas.

Make sure that avast!Antivirus service is not disabled and is started.

You can download TCPView from the SysInternals web site: http://technet.microsoft.com/en-us/sysinternals/bb897437 (http://technet.microsoft.com/en-us/sysinternals/bb897437). No install required. Set it to remain on top of the desktop. You can then get a grip on what is happening as you try to connect to a web site. You should see your browser using a connection to IP 127.0.0.1 to Port 12080. You should see connections by avastsrv.exe to/from IP 127.0.0.1. Finally you should observe a connections from avastsrv.exe to port 80.

By the way, can to connect to your browser home page?
Title: Re: Avast Network Shield Issue - loosing connection
Post by: Popo on November 28, 2011, 10:00:10 AM
Hi guys,

back in the office after weekend...

DonZ63 - I dont have any other proxy servers. With avast web shield off i can connect to https. DNS, and DHCP are set to 192.168.2.1, and that is my routers adress. I tried TCPView, and when i try to connect to google website it shows few connection attempts on diffrent local ports, and they disappear after few seconds. I attached printscreen.

Best regards
Piotr
Title: Re: Avast Network Shield Issue - loosing connection
Post by: DonZ63 on November 28, 2011, 03:42:31 PM
I don't know what to tell you at this point.

I see the Firefox output to 127.0.0.1 port 12080 and that is it. Unless you set up specific firewall rules to the contray, it appears that at least part of Avast is working. It is capturing outbound TCP port 80 traffic from Firefox and rerouting it to localhost TCP port 12080. Then nothing.

Your hosts file in XP is not locked down by other software by any chance? SpywareBlaster, Spybot, SuperAntispyware, etc. all have an option to block access/modification of the hosts file. Maybe forum mods know if a host file lockdown will affect avastsvc.exe operation?
 
Title: Re: Avast Network Shield Issue - loosing connection
Post by: lukor on November 28, 2011, 04:19:51 PM
Hi Popo,
it seems there is something on your PC that is blocking the connection between Firefox and WebShield. I can see WebShield is listening on its port.

AvastSvc.exe: localport=12080, State=LISTENING

Those FireFox.exe connections with SYN_SENT are connections attempt to WebShield, which is also perfectly normal. But here, webshield should response and create the connection between Firefox. Which apparently does not happen at your setup. Either there is something blocking it (a firewall?) or WebShield is somehow !stuck!

If you terminate WebShield in the GUI, does the listening 12080 port wanishes? (if WebShield is stuck, it usually does not responds to stop requests and the port remains opened/in listening state even when the provider was requested to stop).

Thanks.
L.
Title: Re: Avast Network Shield Issue - loosing connection
Post by: DonZ63 on November 28, 2011, 10:36:11 PM
I went through this thread in detail and never saw any reference to what firewall you are using?

If it is other that the XP firewall, see if you have a firewall rule that blocks localhost or 127.0.0.1/255.0.0.0 either inbound or outbound.

If not the XP firewall, a screen shot of your existing firewall rules will greatly help.

Bottom line - avastsvc.exe needs unrestricted access to localhost inbound and outbound.
Title: Re: Avast Network Shield Issue - loosing connection
Post by: ady4um on November 28, 2011, 11:00:27 PM
I went through this thread in detail and never saw any reference to what firewall you are using?

If it is other that the XP firewall, see if you have a firewall rule that blocks localhost or 127.0.0.1/255.0.0.0 either inbound or outbound.

If not the XP firewall, a screen shot of your existing firewall rules will greatly help.

Bottom line - avastsvc.exe needs unrestricted access to localhost inbound and outbound.

Do you currently have any other security tool installed? Or maybe you installed one and uninstalled it later?

In addition, do you have any rules in your firewall related to Avast?
Do you have this problem browsing to any url, or just on specific sites?

Please try with IE instead of FF, just to test if you can use it with the web shield being active.

Please report back.

So, not the first time it is asked. What firewall are you using? Can you delete the firewall rules (for all available "network connections") so to recreate them?

Do you have firewall rules for avastsvc.exe?
Title: Re: Avast Network Shield Issue - loosing connection
Post by: Popo on November 29, 2011, 08:35:18 AM
Hi guys,

Avast updated itself to 6.0.1367 and my problem dissappeared. Thank you for your help. Maybe the solution is somewhere in changelog?

Best Regards
Piotr
Title: Re: Avast Network Shield Issue - loosing connection
Post by: lukor on November 29, 2011, 11:16:21 AM
Hi guys,

Avast updated itself to 6.0.1367 and my problem dissappeared. Thank you for your help. Maybe the solution is somewhere in changelog?

Best Regards
Piotr

Glad to hear that, he have made some minor improvements in the WebShield in this update (for example it now supports WebSocket HTTP Upgrade request) so a few things have changed. Allthough I don't know for sure what was the cause of your troubles I am happy to hear they are now gone! Thanks for the info and patience!!

Lukas