Dale,
Hello, thanks for asking the questions. Fundamentals are the key: Remember the basic function of all switches: Forward, Filter or Flood. Each port us an RJ45 jack using twisted pair cabling (8 conductors and 4 pairs)--1 pair is used for tx, 1 pair is used for rx in a FAST ETHERNET connection.
In your first question: PC1 is connected in port 1 and PC4 is connected in port 4 what will happen when PC1 send data to PC4 and PC4 send data to PC1 at the same time?
PC1 will transmit to PC4 on the sending pair, while receive from PC4 on the receiving pair.
PC4 will transmit to PC1 on the sending pair, while receive from PC1 on the receiving pair.
this can happen simultaneously because of the separate wires.
In your second question: PC1 is connected in port 1, PC3 is connected to port 3 and PC4 is connected in port 4 what will happen when PC1 send data to PC4 and PC4 send data to PC3 at the same time?
Even though the Fast Ethernet defaults to full duplex, in this instance, it won't. PC1 and PC4 will transmit simultaneously but PC3 port will buffer the transmissions to handle it. Then PC3 will receive what will look like a single stream of data. Now, the exception to this is that all switches do it differently in some manner depending on whether the switch is a cut through switch, store and forward etc... the little unmanaged switches will all handle this a little differently.
Cordially,
Ronnie Wong
Host, ITProTV

Great job Scott!
Don't take the Net+ exam too lightly, always better to over prepare! :)
Tim

Jcushing,
Thanks for letting us know!
Cordially,
Ronnie Wong
Host, ITProTV

Thanks, Ronnie!

Got it! Thank you.

I know we discussed POST beep codes in one of the troubleshooting segments, but I cannot remember which one. I specifically remember pulling up the Dell documentation for an OptiPlex 745 to interpret a beep code as well as explain the diagnostic number lights on the front of the case.
Sorry I couldn't be more helpful. I will ask around the office to see if anyone else can pinpoint it.
Thanks,
Don Pezet
Host, ITProTV

I asked around the office and none of us have any experience with OpenWrt. I'll see if I can dig up a compatible router and figure out how it handles VLANs, but I can't make any promises on this one.
Don Pezet
Host, ITProTV

James,
One other thing worth checking is the network card in the Untangle box. Did you buy an appliance, or build your own Untangle box? If you built your own, be aware that not every NIC supports VLAN tagging. Many desktop NICs will strip away VLAN tags before they reach the OS. If you bought an Untangle appliance, then you are fine. If you built your own box, double check the specs for your network card to ensure that 802.1q trunking and VLAN tags are supported.
Don Pezet
Host, ITProTV

Thanks Ronnie. That clears things up a bit.
Cheers,
Steve.

damewoodr,
Glad you're enjoying ITProTV and you're asking a great question!
The answer lies in your subnet mask! If you were to write out your subnetmask of the /22 = 255.255.252.0 This last octet is our only real concern here.
If you were to begin with a 10.0.0.0/8
One network 10.0.0.0, 16,777,214 hosts
With your subnet mask of /22, this means that you can have 2^14 number of subnets= 16,384 possible subnets from that 10.0.0.0/8 network. (I will not do all of them but I will set the pattern of where this begins.
1st - 10.0.0.0/22 00001010.00000000.00000000.00000000/22
2nd - 10.0.4.0/22 00001010.00000000.00000100.00000000/22
3rd - 10.0.8.0/22 00001010.00000000.00001000.00000000/22
4th - 10.0.0.0/22 00001010.00000000.00001100.00000000/22
5th - 10.0.4.0/22 00001010.00000000.00010000.00000000/22
6th - 10.0.8.0/22 00001010.00000000.00010100.00000000/22
...
(notice the interval of 4 in between the subnets--this comes from the fact that we are not concerned with 10 hosts bits) but we are concered with the FIRST 22 bits.)
If you were to copy and paste the above binary into a word proccessor and continue to work it all the way through to 10.55.40.0/22...
Xst - 10.0.40.0/22 00001010.00000000.00101000.00000000/22
Xnd - 10.0.44.0/22 00001010.00000000.00101100.00000000/22

Xrd - 10.0.48.0/22 00001010.00000000.00110000.00000000/22
Xth - 10.0.52.0/22 00001010.00000000.00110100.00000000/22
The /22 give you an interval of 4 because the 22nd bit is in the 3rd octet with a place value of 4. So your network ID numbers will always be increments of 4.
Hope this explaination helped you.
Cordially,
Ronnie Wong
Host, ITProTV

Brian,
I didn't mean to overstep, I wanted to provide an answer about the differences since that is the first question I saw was about clarifying the differences between the connectors.
Cordially,
Ronnie Wong
Host, ITProTV

shlomgad,
I saw this post just yesterday, but we believe the link is now fixed.
I browsed to it from the Course Library, Comptia, Network+ and the overview page. There are now two links, one for the main link and the one for (Part2). Yesterday, there was the same link for both. Hopefully, we've fixed this for you.
Please let us know if you have any subnetting questions that we can help you with in your studies.
Cordially,
Ronnie Wong
Host, ITProTV

James,
Good to hear from you. I did a search on www.newegg.com for ethernet hubs and found some, like you said from $20 to over $200. Like all things, when the supply is short the cost is high.
Even though, I understand your desire for 2 separate IP networks. Your solution on using hubs is not a good one for the sake of what you want "absolute security." By using a hub, any one single port still gets the any electrical signal sent from any one port. This will be true regardless if you put all of your devices on different IP networks because of the basic functionality of the hub.
You've got a few options though like you've mentioned. The only way to guarantee that your two networks will never be able to directly connect to each other directly is to put them on completely separate equipment. Or you can use two hubs, each directly connected to your router on separate router interfaces.
I would recommend the usage of a switch with vlans. The cost is a little more but as you're seeing the cost of hubs are not a lot less anymore. With the switch, you can create your 2 separate vlans and use a single router port (100 Mbps or higher) along with access control lists on your router to keep the traffic separated.
Cordially,
Ronnie Wong
Host, ITProTV

Congratulations! You're doing well to get the correct answer! Thanks for the question.
I hope the answer below helps you.
Question: How many subnets and host per subnet can you get from the network 172.23.0.0 255.255.255.240?
We start with the idea of understanding that the base network is a class B network:
172.23.0.0 255.255.0.0 = 1 netowrk, 65534 possible hosts on this network.
If you now add an additional 12 bits to the network portion (the break down: 16 bits NetworkID,12 bits SubnetID, 4 bits HostID). You've taken ONE netowrk and created 2 to 12th power number of "subnets": 2^12 = 4096 networks. The remaining bits that are not associated with the network bits and subnet bits would be 4 bits for the Host bits. This gives you the 14 hosts per network. (For the host bits even if there are 16 possible combinations, we must subtract 2 -- 1 for the NetworkID, 1 for the BroadcastID).
Question: 172.16.0.0/18, how many subnets?
We start the same way: 172.16.0.0 255.255.0.0 is the base network (1 netowrk, 65534 hosts on this network). the new subnet mask= 255.255.192.0
If we add an additional 2 bits the network portion: (16 bits on base NetworkID, 2 bits as SubnetID, 14 bits as the hostID bits). So we would have 2^2 = 4 subnets we could create with each network having 2^14 = 16382 hosts per subnet.
Let us know if we need more explanation!
Cordially,
Ronnie Wong
Host, ITProTV

wvykid,
It's been a while since we filmed that episode so my memory is a little fuzzy but here is how I remember it.

For the initial installation of pfSense we hooked a monitor and keyboard directly to the firewall box and did the local install. Once that was done we switched to my laptop for the rest. We didn't discuss it on the show, but I had two network adapters on my laptop. One NIC was connected to our studio network so that I could share my desktop with our video switcher. The other NIC was run to a switch which then connected to the LAN interface of the pfSense firewall. That effectively placed me on the inside of the firewall network and allowed me to access the web UI for configuration. Since my laptop had two default gateways, I manipulated my network interface priorities to ensure that my outbound traffic went through the firewall. I don't remember specifically, but the DMZ interface was either unplugged or we stuck a loopback plug in it to bring the link up without actually plugging it in to a network. Either way, the DMZ interface was not connected to a real network. The WAN interface was plugged in to our studio network so that the firewall had internet access. From there we were able to configure firewall rules to block/allow traffic as it passed between the firewall's LAN interface and the studio network.
I think that sums it up, but if you want any other details just let me know.
Don Pezet
Host, ITProTV

Chad,
I answered one of your other posts explaining how the new arrangement works, but I understand this was a pretty important feature for you. I'll pass this on to the web team and see if it is something we can bring back.
Thanks,
Don Pezet
Host, ITProTV

Tim,
A+ was the very first show we recorded, and as a result they are our lowest quality shows. We have slowly been re-recording them now that our production quality is higher. The episodes you have listed are ones that have been superseded by new episodes and have been removed. So while the episode numbers may seem incomplete, the episode list on the course page covers the whole exam (or in this case two exams).
Sorry for the confusion,
Don Pezet
Host, ITProTV

Joshua,
Thank you for the feedback. We had a particularly hard time finding software that generated the right mix of compatibility issues for that show and settled on the firewall software because it exhibited the symptoms we needed. Originally our producer had intended for us to use an old skiing game but it turned out it required the 16-bit sublayer and there was no way to make it work on the newer OSes even with the compatibility settings as 16-bit software is no longer supported. I would have to go back and watch the episode again, but I seem to recall one of us mentioning that it was a bad idea to run the firewall software during the episode. If we didn't, we can easily add an errata to the episode but I think it might be a "Caution: Coffee is Hot" type issue that goes without saying.
Thanks again,
Don Pezet
Host, ITProTV