In my GNS3 lab work, I often experience issues closing the program. It’s even annoying and sometimes a pain in the ass,
I’ve searched on the Internet for a while. I even thought about switching my whole lab to Linux. This won’t be a good idea for my CIPTV1 studies, because I have IP Blue and X-Lite softphones that only run on Windows. Besides, I have a couple of Virtualbox VMs that I’ve built delicately and whose transition to Linux won’t be easy.
I pinged the localhost IP address to see if I really can reach it:
Apparently, I was wrongly accusing GNS3. It seems there is a issue connecting to the 127.0.0.1. I remember from my past college days that network connectivity to 127.0.0.1 must be established to confirm that TCP/IP is correctly installed on the computer. So there must be something with the firewall.
I’m using Comodo Free firewall. Although you may think it’s not that good because it’s free, I find it great and easy to use.
I disabled Comodo firewall:
And I pinged 127.0.0.1 once again:
Now it works. I now confirm it’s a firewall issue. But I don’t want to disable my firewall altogether. I must create a security rule that allows IP traffic to 127.0.0.1. In Comodo firewall, you create a network zone and allow traffic to it.
Here’s how to do it in the GUI of Comodo firewall:
Defining the network zone for 127.0.0.1
Go to the main menu and click on Firewall
Go to Network Zones
In the network zone area, click on the bottom arrow:
then click on Add
Click on New Network Zone
Type the network zone name. I named it loopback Zone. Click OK
In the menu, select the loopback Zone network zone and click Add –> New Address
Select IPv4 Single Address and define the local loopback address 127.0.0.1.
click OK to commit the changes.
Defining the global rule that allows traffic to 127.0.0.1
Go to Firewall –> Global Rules
click on the bottom arrow then Add
Allow IP traffic, inbound and outbound. Name the firewall rule by giving it a description. And define the Source Address as “Any Address”:
In the “Destination Address” field, set the Type to Network Zone, and the zone to Loopback Zone:
In the IP Details field, set the IP Protocol to Any:
Click OK to commit changes.
Switch the firewall back on.
If you did a continuous ping earlier and the ping did not fail after you commit the firewall changes, it means you established connectivity to 127.0.0.1 successfully through the firewall.
Testing the result by opening and closing GNS3
After all the customization made to your firewall, open your GNS3 file and close multiple times. Normally you will no longer encounter the “waiting for http://127.0.0.1:8000” error any more. And my computer no longer freezes when I close GNS3.
Another trick that can reduce your CPU utilization is by changing your hubs with a layer 3 switch. The trick works if you connected more than one device on a single hub.