The TCP/IP stack is a networking model that describes what happens to data in transit from one application to another. How does it differ from OSI? The TCP/IP stack is just another model, similar to OSI. At the end of the day, TCP/IP stack aims to describe the same thing that OSI does. It’s just a different description. Like learning the same subject from two different people. The layers: Application Transport IP Link Application This layer defines what data is to be sent and “encodes” it so that the receiving application can understand it.

Had to write this down. I’ve been trying to get up and going with KVM recently. I got a break from school and need KVM up on my home server so I can experiment with many other things. I read through a bunch of the libvirt documentation, specifically about virt-install, and then once I had a grasp I ran through some tutorials. Most of the tutorials I found out there and virt-install one-liners had me using a network option as follows:

Just a quick note, I had to open up a hole in the firewall on the server itself (even though I had my router stuff all set right already) by doing: <i>sudo firewall-cmd --permanent --zone=public --add-port=80/tcp sudo firewall-cmd --reload </i> Worked great. I guess having a firewall on the server itself is good too. Instead of just relying on the one on the outer edge of the network.

So I have been trying to figure this out. I am supposed to be able to do some port forwarding, which isn’t hard, but it wasn’t working. Eventually I went with the option of setting up two network adapters, one set up on NAT (so the VM can access the www) and another as a host-only, so the host can access the guest on 192.168.x.x I was having a problem though, it was refusing me.

Just was playing around with it, wanted to write a few things down. I typically use telnet to test for a particular port. Essentially the basic usage is: nc some.domain.com 21 That will connect to some.domain.com on port 21 if possible. What I want to use it for though is to just quickly check a series of ports. Here’s the command I like currently: nc portquiz.net 21 -zv the -z only checks for connection, but /dev/nulls any response from the server.