Cool very interesting!

taking a few mins to watch this!

@scottalanmiller said in Network Services - CompTIA A+ 220-1001 Prof Messer:

@valentina said in Network Services - CompTIA A+ 220-1001 Prof Messer:

are proxy servers used for security purposes? do they have other functions?

Yes, very much so.

They are also very commonly used to allow a single IP address to be used for many services. The most common example... a single proxy server with a single (expensive) public IP address can handle requests for hundreds of thousands, or even millions, of websites. Behind the proxy server can be one or one million separate web servers each serving out applications or web sites or whatever and the proxy server can look at the incoming request and determine, based on the URL used, which server and port to send the request to behind itself.

Because of the above, they are often used for load balancing because they can send requests to different servers for the same application or site.

Proxy servers often have caches in them, too. So they quite often store simple, static information "at the edge" to deliver it faster while the application servers behind them do the heavy work for database requests and stuff.

Proxy servers are sometimes used to "hide" the true location of a server. Cloudflare famously does this so that attackers have no idea where a web site actually comes from, all they see is Cloudflare's proxies.

A proxy can also do things like handle SSL security so that web servers behind it (or other servers, proxy doesn't imply web) don't have to do that work, as well.

Hrm, I only have around 20 subdomains pointing to the same IP so far. If my home lab box was a little beefier I'd take this as a challenge. (Scott might as well be describing my home lab environment here.)

Interesting

Done with this one!

@Dashrender said in Installing a SOHO Network - CompTIA A+ 220-1001 Prof Messer:

@scottalanmiller said in Installing a SOHO Network - CompTIA A+ 220-1001 Prof Messer:

@Dashrender said in Installing a SOHO Network - CompTIA A+ 220-1001 Prof Messer:

@scottalanmiller said in Installing a SOHO Network - CompTIA A+ 220-1001 Prof Messer:

Think about a thermostat that you can connect to online. The thermostat IoT device is in your home. The IoT vendor has a server. You work with the thermostat through the hosted server somewhere. If that server was compromised, bad guys could run up your AC bill.

To bad most cameras don't work that way - instead they use uPNP to open ports and just spew your video feeds to the world.
https://www.insecam.org/

"Most" of anything is crap. No good camera does that. What a bizarre system.

Agreed - but it's very likely type of equipment they'll run into out in the wild.

I've never seen that with a client in the wild. I'm sure it happens, but it's not something we really run into. Common with home users, for sure. As business class routers don't allow that, it limits it in the field a lot.

And it's not like we don't see cameras, worked with a security company just today!

Also, lots of customers on cheaper or less "business" equipment often have double NAT which while awful, stops UPnP.

Done with this one too! Reading the comment section : - )

@scottalanmiller ahhhh the S.A.M.

One of the clear problems with the CompTIA A+ has always been that it clearly caters to promoting Microsoft products and not being vendor neutral as it has always claimed to be. With the latest release, literally half of the exam is Windows only. There is no section for macOS, any Linux, iOS, Android, Chromebooks, nothing, nada. It's become a Windows exam, which means that they don't just skip the underlying principles that they claim the exam is about, and skip the neutrality for the industry that they claim it is about, but they also leave people going into entry level positions totally unprepared for the real world where running into non-Windows OSes is common. If you were learning from nothing but the A+, you might not even be aware that non-Windows exists. Let alone non-PC hardware, which appears to also be completely skipped.

This was very informative, I like the simplicity of the explanations. Also @scottalanmiller thanks for the extra feedback! I watched this a week ago btw

@connorsoliver said in An Overview of RAID - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer:

Is using a RAID 1 configuration faster as well? Or is its main purpose so if you lose one of the drives you have a backup?

Primary purpose is definitely data protection. But RAID 1 provides a 200% read performance benefit over using a single drive. Write performance is the same as a single drive.

@connorsoliver said in An Overview of Storage Devices - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer:

What did he mean when he said there's only a limited number or writes on a USB flash drive.

So this is a small mistake on the A+ material. They are making assumptions about the storage media based on the communications protocol. But it's based on very common things. A standard USB flash drive using a flash memory technology that "wears out" as you write to it, but essentially never wears out as you read it.

So the way that a USB stick is "meant to be used" is that you store things on it and read it a lot. You can change it, but it isn't meant for constant writes.

So under "normal" use, USB sticks last a long time. But it you write to it constantly (like when using it as swap) you will cause the memory chip(s) to die quickly.

@connorsoliver said in Installing and Configuring Expansion Cards - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer:

I've seen that people have used two graphics cards in a setup. How does this work exactly? I'm assuming you don't use the video outputs of both graphics cards.

Generally it is handled by a proprietary "bridge" for those specific cards that makes two (or more) cards act as one. Same as have two CPUs in a single PC.

@connorsoliver said in Understanding PC Memory - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer:

What exactly does registered memory do?

Wikipedia has about the best explanation of this. Mostly we ignore this, IT people really don't think about registered vs non-registered memory, that's something bench people worry about or your server vendor, but not IT. CompTIA mentions it because it is a bench exam.

Registered (also called buffered) memory modules have a register between the DRAM modules and the system's memory controller. They place less electrical load on the memory controller and allow single systems to remain stable with more memory modules than they would have otherwise. When compared with registered memory, conventional memory is usually referred to as unbuffered memory or unregistered memory. When manufactured as a dual in-line memory module (DIMM), a registered memory module is called an RDIMM, while unregistered memory is called UDIMM or simply DIMM.

Registered memory is often more expensive because of the lower number of units sold and additional circuitry required, so it is usually found only in applications where the need for scalability and robustness outweighs the need for a low price – for example, registered memory is usually used in servers.

DDR2 uses a clock speed twice as high as the bus speed. So DDR2 is double the speed of DDR given the same bus. The clock that the computer provides to the RAM is the same speed. But the memory clock speed in these cases as either 1x or 2x the bus speed from the computer. So the clock speed is double.

@travisdh1 said in Motherboard Jumpers and Connectors - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer:

@Dashrender said in Motherboard Jumpers and Connectors - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer:

@travisdh1 said in Motherboard Jumpers and Connectors - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer:

@connorsoliver said in Motherboard Jumpers and Connectors - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer:

Why are jumpers a thing? It seems like there would be a more effective way of doing the things that they are used for.

I think the last jumper I used was the last IDE HDD I used. That was at least only a single jumper to deal with.

Anyone else remember the days of 486 boards and the masses of jumpers to set all the board settings instead of having everything set in the BIOS?

486, you youngin'. 😛

I was messing with computers all the way back to the 80-86 days, just didn't have one at home till the 486 era.

The first computer I purchased (at age 13) was an 8086. though I think 286 or 386's were out at the time.

@connorsoliver I went on an image search of motherboards this morning. The Asus 99 deluxe only has a south bridge if you want to take a look.

@connorsoliver said in CPU Sockets - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer:

Is the LGA or PGA configuration more common in CPUs?

LGA is more common. And getting even more common in the future.

@connorsoliver said in Motherboard RAM Slots - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer:

What exactly does RAM affect in a computer? I'm assuming it has to do with speed right?

Not really. But kind of. It's complex. "Speed" is not at all the simply idea that it seems like with computers. There is so much more to it. Speed under what workloads, for example.

@connorsoliver said in Motherboard Expansion Slots and Bus Speeds - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer:

I sawn in this video that it talked about 32 bit and 64 bit connections. Does this have anything to do with wether your computer is determines as a 32 or 64 bit machine?

The system bus has nothing to do with weather your CPU is 8/16/32/64 bit. ISA/VESA/AGP/PCI/PCIx are all independent of the CPU.