FYI: A tale of two firewalls and network dropouts

ubuysa

The BSOD Doctor
Like most folks on here I know that having two firewalls active at the same time can be troublesome, but until I accidentally managed to do it the other day I hadn't realised just how troublesome it can be. I thought my experience would be useful, especially to those searching these fora for network dropouts and inconsistent Internet connectivity solutions.

I run the Comodo Internet Security suite (CIS) and have done for donkey's years. It has an excellent and hugely configurable firewall so I've always been careful to make sure that the Windows firewall is off. I generally do that via the Local Security Policy because I've found that Windows has a nasty habit of turning the firewall on if you just turn it off via the Control Panel.

A couple of days ago I decided to do a reinstall to fully clear out all the clutter from the great many installed and then uninstalled software that I like to experiment with. To save time, some months ago I created a disk image (via Macrium Reflect) of a clean install of Windows 8.1 plus all the original PCS-supplied drivers and all the Windows updates available at that time. So to do a clean install I simply restore that image and proceed from there, it saves quite a bit of time and messing about. Unfortunately, when I cut that disk image I had not turned off the Windows firewall and, like the numpty that I am, I forgot about it after restoring that image. So after installing CIS I had two active firewalls.

Everything looked good after all my third party software was reinstalled and I was a happy bunny. At least until the radio station we stream via the Internet every day (ClassicFM) started to loop quite often - indicating it had lost contact with the server. I put this down to a busy server a ClassicFM, but then I noticed that occasionally and almost at random I'd fail to connect to a website, a refresh of the page brought it back with no problems. A little voice started to whisper in my ear that this wasn't normal but I put it down to congestion in the network (I use a MiFi for Internet access). Still, these random failed connections and ClassicFM loops kept happening at all times and with no apparent rhyme or reason. It wasn't related to the performance of my Optimus IV, all resources were not even breaking sweat.

It wasn't until my wife had decided to listen to ClassicFM on her smartphone because she couldn't stand the random looping that I realised that it was my Optimus. Whilst ClassicFM was looping (lost connection) on my Optimus it was playing perfectly fine on her smartphone (connected through the same MiFi).

I won't bore you with the long and fruitless problem determination path I took but eventually the penny dropped and I realised I had two firewalls active. A quick trip into the Local Security Policy editor and the Windows firewall was deader that the dead thing from the dead place. All my connectivity problems vanished, the clouds parted and the Sun came out.

So, the moral of my story is: If you're experiencing random network dropouts, poor connectivity, random page loads failing, or any other curious and seemingly random Internet issues, and you use a third-party firewall (as many do) do please check that the Windows firewall is turned off!

The is an ancient Chinese proverb (well, there should be anyway) that says; One firewall good, two firewalls stupid...!

:)
 
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