the linkoptimizer.dll file is being detected as trojan by avast and i always delete it. My problem is that the linkoptimizer.dll somehow reinstalls itself from time to time. It doesnt seem to be a problem for Avast because it detects it every time but i would like to know how i can stop this trojan from installing itself. I have run several Ad-removal tools but without success so far.
Does anyone have experience with this trojan?
im using ad-aware SE, Avast and Sygate Pers. Firewall.
It looks like there is another element that is re downloading it.
If you haven’t already got this software (freeware), download, install, update and run it, preferably in safe mode. Ewido Security Suite If using winXP. or a-Squared free if using win98/ME.
I would also suggest adding the following:
Spybot Search and Destroy
Spywareblaster Don’t install this until you are clean.
Your firewall not only is no longer being developed (having been bought out by Symantec) but it has a flaw/vulnerability, in that it can’t identify programs using a localhost proxy (like web shield). Since the web shield has permission to connect, anything that used that proxy will also inherit that permission. I thing it is time to look to your options.
Zone Alarm free http://www.zonelabs.com works fine with avast and has a reasonably friendly user interface. There are others, Comodo, Jetico, Sunbelt Kerio, etc.
See some firewall tests for comparison, some are freeware but many are paid for versions http://www.firewallleaktester.com/tests.php.
Any malware that manages to get past your defences will have free reign to connect to the internet to either download more of the same, pass your personal data (user names, passwords, keylogger retrieved data, etc.) or open a backdoor to your computer, so outbound protection is essential.
Hi shouwaronin,
As DavidR says a downloader agent is at the base of this, read here: http://www3.ca.com/securityadvisor/pest/pest.aspx?id=453088440
After you cleansed your system, update and patch your OS, and install apprpriate protection as proposed.
polonus
thx for your help.
i have installed the ewido suite and scanned my system in secure mode and in normal. Additionally i have used Spybot and Hijackthis. I found quite a number of “infected files” and removed all of them although many were just cookies for login information for certain sites. But the problem is still not solved. The linkoptimizer.dll still installs itself from time to time.
I have tried to install Agnitum Outpost Free version but i cant use my browser afterwards. Even if i deactivate Outpost i dont get an internet connection. Im using WLAN and a client which my Sygate identifies as a seperate connection. Outpost doesnt seem to recognize it, could that be the problem?
Outpost Free hasn’t been updated for some considerable time, that is one of the reasons I switched to the Pro version.
Check the Outpost, Options, Application, and see if it allows (trusted) or has blocked ashWebSv.exe.
Outpost Pro was a good firewall before adding adware scanning (just to update frequently, test the genuinity of the software in my opinion… just antipiracy feature).
It’s a shame they’ve stopped to developed the free version. Kerio has much more to give in the free version, in my opinion 
Outpost Pro still is a good firewall, one of the best, you don’t have to have the anti-spyware plug-in, it has been disabled on my system from day one of its introduction.
Yes it is a shame about the free version, but it is now just a hook to get people to convert to the Pro version. Unfortunately that is a double edged sword if the free version isn’t developed it will be a poor advert for the pro version.
This is my case 
thx for the tip with Kerio. I have tried this firewall too, but i have the same problem. After installation Kerio recognized my WLAN Connection and asks if it is my trusted connection. After i have allowed the connection it also recognizes the AVAST updater and other avast services and even when i open my browser it asks for confirmation. But still i cant surf the web. Do i have to make any adjustments in the internet options of WIN XP ?
What i dont understand, why cant i surf the web after i have deactivated the Firewall? Both, Outpost and Kerio, have this problem. I have to deinstall them (i havent tried to prevent their autostarting → maybe another possibility?)
As a last resort im using the integrated NVidia Firewall of my Asus Board. I wonder if the linkoptimizer.dll will get through this one, too.
Do i sound desperate?!?! Paaaalleeeeeaase help me. DIDI wrecked my PC !!!
Into the firewall settings, the following programs should be allowed to connect:
C:\Program Files\Alwil Software\Avast4\ashWebSv.exe (avast! Web Scanner)
C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe (avast! e-Mail Scanner Service)
C:\Program Files\Alwil Software\Avast4\Setup\avast.setup (avast! Update executable)
Don’t need rights to connect:
C:\Program Files\Alwil Software\Avast4\ashServ.exe (avast! antivirus service)
C:\Program Files\Alwil Software\Avast4\ashUpdSv.exe (avast! Update Service)
Can you check?
When Kerio is activated, is the Windows XP firewall disabled?
i have installed Kerio again and checked the application list. AvastWebsv and Avastemail were allowed to connect. Strangely avast.setup was not even listed and Avast also had failed to update (red box popping up in the lower right corner).
My windows firewall is deactivated and the security center of WinXp is also deactivated (services).
I have tried to disable Kerio afterwards but couldnt find it under “msconfig - autostart”. Then i found it under services and deactivated it. But after the restart of windows, i still wasnt able to browse the web. What exactly are those firewalls doing? Do they change any TCP protocols or proxies?
The same problem with Agnitum Outpost. there are no applications under the “blocked” tab. Everything is permitted.
In the past i had used Outpost with ISDN (64kbit internet) via cable. I think it has something to do with my WLAN. Im using a router and a siemens WlAN Usb stick.
I won’t say strangely as if it is not there, no update is possible.
avast.setup is a temporaly file that is created just before update and starts the process. It should be allowed to connect.
In my Kerio settings it is there
I don’t think this is the best to do… why don’t you just disable it throught the icon on system tray?
Kerio does not change anything, just check and block, check and allow.
Wow… are you using two at the same time?
sorry for my bad english. maybe you misunderstood me.
I meant there is no difference between disabling Kerio through the tray icon or through the services.
Shouldnt i be able to connect to the internet after i have deactivated Kerio?
Only after i have deinstalled it i am able to connect to the internet again.
And i meant i have the same problem with Outpost. Im not running Kerio and Outpost together. I have only installed one Firewall at a time.
hmm although … could there be a conflict between my NVidia Mainboard Firewall and Kerio? When i have installed Kerio i only deactivated the NVidia Firewall. But the NVidia Firewall is part of the Mainboard drivers, so im not sure if its good to kick it out.
By the way Kerio does not have any applications it should block. there are only permitted once or applications it should ask for permission.
Thanks for your time and energy. I have the feeling im getting on your nerves right now 
somehow i have forgotten that this is not a firewall forum, but nevertheless i really appreciate your help.
Hi shouwaronin,
Also consider this:
http://forum.avast.com/index.php?topic=398;prev_next=next
greets,
polonus
Yes… if only Kerio is what is blocking the internet connection…
Do you use any other security program? Do you use a proxy?
I never heard about Nvidia firewall… but, most probably, yes, should be a conflic
Couldn’t you find more info in their website or Googling?
No… I’m not nervous… just curious about what’s happening, just trying to learn, just enjoying avast forums 8)
Yes... if only Kerio is what is blocking the internet connection... Do you use any other security program? Do you use a proxy?
No i only use Ad-Aware SE, Avast and Ewido right now.
To my shame i dont know where to setup my proxy. Im using Avant Browser which can import proxy settings. But right now it only says its using Internet Explorer Settings. But i dont know where i can find the Internet Explorer Proxy Settings.
hmm although ... could there be a conflict between my NVidia Mainboard Firewall and Kerio?
Yesterday i have deinstalled my Nvidia Firewall. But there was no change. After i had installed Kerio, i couldnt connect. Another problems which occurs when i install Kerio is, that my Wireless Connection says it is somehow limited and not fully available.
No... I'm not nervous... just curious about what's happening, just trying to learn, just enjoying avast forums
Uhh, now im getting nervous ;D
Open Internet Explorer, go to Tools > Internet Options > Connections (tab) > Lan configuration buttom > uncheck the proxy option if any.
Into avast settings, try switching the proxy settings from “Auto-detect” to “No proxy”: Left click the avast icon > Settings > Update (Basic) > Details > Proxy
On Kerio settings, go to Network security > Trusted area.
Can you post a screenshot of this window?
i have written a mail to Sunbelt Kerio and got a response with some standard steps (regarding trusted zones). But it wasnt a big help.
The proxy settings of IE are off and the avast settings are also off.
Here is the image.
I have three entries too, but:
I think you must remove from trusted zone the Internet adapter of yours. I guess it is the last one, but I can’t be sure. You must post a sreenshot of your IP settings for the Internet card.