@mary said in Software-Defined Networking - CompTIA Network+ N10-007 Prof Messer: Is there specific software that is used for creating a virtual environment? SDN refers to a great number of potential solutions. In most cases, it is software built into the hardware. So Cisco, Juniper, Brocade and other networking makers offer software solutions, often that have no particular name. They are just the SDN options of that gear. Pure software does exist and a common example of it is ZeroTier which is designed as a complete virtual networking layer on top of your physical network and has no interaction with the underlying hardware so it completely agnostic.

@mary said in Circuit Switching and Packet Switching - CompTIA Network+ N10-007 Prof Messer: Is there anything not considered packet switching? Yes, the most common example is the voice network (the PSTN / Public Switched Telephone Network). It establishes a "circuit" for every call, and it is permanent until that call ends. It switches on a "call by call" basis. Every packet associated with that call takes the same path. It is almost always considered archaic to use circuit switching, it is rarely useful or efficient. It was popular in the "pre-data" era of networking when it was audio and video, generally analogue, going over the path rather than individual packets. Now that we have packetized data and the power to evaluate the route every packet, there is little to no purpose for circuit switching.

@mary said in Access Control Lists - CompTIA Network+ N10-007 Prof Messer: Is there a way to deny all incoming traffic to your firewall? Sure. But if you think about it, you'd absolutely never want this. This would be the same as disconnecting the network. If you wanted to do this, you would simply unplug the network instead (as that is more reliable.) The only reason to truly "deny all" is to go offline. And if you want to be offline you logically want it to be really reliable and since you'd want no traffic to make it no matter what in that situation, pulling the plug is the better choice 99.99% of the time.

@mary said in Network Address Translation - CompTIA Network+ N10-007 Prof Messer: Is there any kind of slowdown when using just one port if you are getting a lot of traffic? No not really. The most commonly used ports are 80 and 443. They process quite a bit of traffic on your average workstation. In fact, most servers are designed to work with a single port or just a handful of ports open. For custom applications using a specific port makes it easier to troubleshoot issues and restricts non application traffic. Many apps are defaulting to 443 these days. Although, keep in mind SSL /TLS can operate on other ports.

It only kicks in when a pipe has hit saturation. Even if you're at 99% bandwidth, there would be no prioritizing because the packets would just flow in the order they are received. So the answer is, it totally depends if your pipe is ever saturated.

@mary said in Configuring IPv6 - CompTIA Network+ N10-007 Prof Messer: When using ipconfig on a network I've seen the IPV4 and IPV6 addresses shown at the same workstation. Sometimes it shows IPV4 (preferred). Why is that? I don't have a specific reasoning - but I'm guessing it's because the computer received a DHCP reply on IPv4 - so the computer assumes that IPv4 is the primary way this network wants to communicate.

@mary said in IPv4 and IPv6 Addressing - CompTIA Network+ N10-007 Prof Messer: If you are using :: to abbreviate sets of 2 or more zeros, how can you tell how many there are? In the example he condensed 3 sets down to ::? IPv6 always has 8 sets of 4 numbers for addressing. So it should be easy to figure out with a little math. IE: FABD:4976:5AC3:: would mean that 5 more sets of 4 zeros is tacked on FABD:4976:5AC3:0000:0000:0000:0000:0000

He mentioned proprietary protocols. Do you always have the option to choose between the standard and proprietary or do some force you to use the proprietary?

@mary said in IGP and EGP - CompTIA Network+ N10-007: Hiw important are the different types of protocols for IPV4 and 6? Pretty important, but not things any normal IT pro will ever see. Routing protocols are only modified by large companies, and only by dedicated network admin staff.

@mary said in Static and Dynamic Routing - CompTIA Network+ N10-007 Prof Messer: If you can set a default route, why would you use static over dynamic? Static routes require a human to modify them anytime anything changes. So, for example, the route you want fails because a device dies. If you have static routing, then you simply go offline until you go and change the route to something else manually. When the device is repaired, you won't go back to the optimum route until such time as someone manually puts it back. With dynamic routing, the protocols look for the best routes at all time and can not just adjust for failure conditions, but can also detect new routes that are better when they appear, go back to repaired routes, detect congestion and adjust routes based on temporary traffic conditions, etc. Think of one as having a map telling you how to get from point A to point B and if there is road construction or loads of traffic or an accident, that you just have to sit there until your route clears up. And dynamic routing like a GPS that adjusts based on real world conditions and gives you an alternative route should your main one be blocked or slow.

@mary said in Spanning Tree Protocol - CompTIA Network+ N10-007 Prof Messer: If you have a bad switch are you informed in any way? Generally no. "Bad switch" is an awfully general thing. Most switches are "dumb", just simple boxes with zero communications with the outside world. A good, managed switch might have some alerting, depending on how it fails, and how you are monitoring it. the problem with any device failing is that it generally does not know that it is failing or it wouldn't fail. Switches are very core so rarely can detect their own failures. Mostly you detect switch failures from there being problems on the network and just testing. These days switches have a tendency to just die, or just work. In the past you used to have a port here or there that would fail. Switches failing can do weird things, but often just give up and quit on you.

Is there a limit to how many trunks you can use?

@mary said in Protocol Data Units - CompTIA Network+ N10-007 Prof Messer: Why aren't the values automatically deducted when sending information out if we know the length needed for the OSI layer? It could be in that case. But the big protocols used today like Ethernet, IP, and TCP don't have predictable lengths. ATM was an Ethernet competitor that was popular back when hardware was limited and fixed lengths were faster to process. That proved to be useful 20+ years ago, but quickly became unpopular as hardware got much more powerful very quickly.

It's more purpose based. Unicast is for normal communications. Broadcast is normally reserved for special cases like DHCP where there is no way to do unicast.

Can anyone give me an example of a broadcast domain? This seems a bit basic. It made me think of things like push notifications, so I'm not sure if I'm getting the concept.

@mary said in Network Switching Overview - CompTIA Network+ N10-007 Prof Messer: Does the communication between 2 switches need to be configured Totally automatic by default. But you could, in theory, set the port speeds, set a VLAN, or similar settings. But the average switch is unmanaged, meaning that no configuration is possible.

@mary said in Introduction to Ethernet - CompTIA Network+ N10-007 Prof Messer: A little disappointed that he spent 10 mins of this video on hubs and only 3 on stuff we may actually work with. They might be old, but understanding them is definitely important because it tells you a lot about how the underlying network behaves.

@mary said in Common Ports - CompTIA Network+ N10-007 Prof Messer: @scottalanmiller makes sense. He did say outgoing to a DNS server. Thanks UDP itself has no connections, but that doesn't mean that a protocol running on top of it can't have its own connections. TCP makes connections for you, UDP requires you to do it yourself (if you want them.) So important to know that UDP itself does one thing, but can be used as a tool to make other things.

@FiyaFly said in Introduction to IP - CompTIA Network+ N10-007 Prof Messer: @scottalanmiller said in Introduction to IP - CompTIA Network+ N10-007 Prof Messer: Humans do tend to get confused a bit on ports. Here are some things why... TCP and UDP have the same port ranges but are different protocols and TCP ports are unrelated to UDP ports. So TCP Port 22 can be doing one thing and UDP port 22 something totally different. Ports under 1024 are traditionally designated by the operating system as protected and require admin level to open. Ports at 1024 or higher can be opened by anyone. But that is an operating system thing, not a networking thing. But important to know. TCP and UDP are not the only protocols and not every situation has a port. ICMP doesn't use TCP or UDP and does not use ports at all, for example. TCP is connection based, UDP is connectionless. So people often get confused with UDP because you can't "open a connection" to see if it is working. Even people with 20 years of experience forget this constantly and fail to troubleshoot. I'll tell you a UDP joke, but I'm not sure you'd get it. Might tell you another UDP joke, but I'm not sure you'd get that either. But then, I'll tell you a TCP joke, and I know you'll get that one. I laughed out loud at my desk and my coworker didnt understand the joke. HA

@mary said in Windows HomeGroups, WorkGroups, and Domains - CompTIA A+ 220-1002 Prof Messer: Is there any alternative to home group now that it isn't available on Windows 10? Also why would you use workgroup instead of Windows Domain? Is it a cost issue? "Home Group" was just a fancy name for network sharing without AD on Windows computers.

@mary said in Windows Control Panel - CompTIA A+ 220-1002 Prof Messer: This may be basic but, can cookies damage your system in anyway? It's one of those things that a lot of sites require you to accept, and an average user just accepts them. So the cookie itself is just a text file. A tiny one. That's it. So the cookie itself does nothing. The issues are if the cookie has something in the text and a browser reads it and does something it shouldn't because of it. But realistically, that's not going to happen. The main concerns around cookies are that they help people to track you, but you need to be tracked. We've been conditioned to thinking that being tracked is a bad thing, but cookies are what lets us track you from post to post here in RoIT for example.

Pretty useful stuff. I played around with some of the commands on my laptop.

@mary said in Windows Task Manager - CompTIA A+ 220-1002 Prof Messer: Do any of you use task manager to troubleshoot what if there is an issue with a PC? I'm trying to get a sense of the steps people go through. Constantly. If working on Windows, it's the "go to" starting point to "see what is going on." It's not a once in a while tool, it's the "might as well just always start there" tool. It gives you a quick glance to see what the system itself is doing. If CPU or RAM is maxed out, or a process list looks crazy, that's almost always what is wrong no matter what it is that you came to look at! I mean if I'm looking for a missing folder of cat pictures, I don't open the task manager first. Nor if I'm installing a new printer. But if I am troubleshooting anything going on with the system, that's the first place to look. The Resource Monitor is also pretty fantastic.

Pretty straightforward.