Need some advice on learning networking

[Phil B.]

Re: Need some advice on learning networking

192.168.10.2 and 192.168.20.2 are just IP addresses. A subnet mask of 255.255.0.0 will allow communicating with every device on every subnet of 192.168. Changing the value of the third octet would restrict the number of subnets and changing the value of the fourth octet will restrict the devices on each subnet. I would have to look up the proper tables to tell you what each value would yield and I don't feel like doing so right now.

He can look all that on the net.
I like Duck Duck Go and Yahoo search engines.
Search network IP/sub net addressing or some such.

Sent from my SM-G960U using Tapatalk

[BillyCarpenter]

Re: Need some advice on learning networking

For 2 days I've been trying to get back to my practice lab on sending DHCP addresses across inter-vlans but because I had had weak areas in my knowledge, I had to go back and fill those gaps. This is a lot of information to take in at one sitting. Take my word for this....you don't want any gaps in your understanding of networking because it will come back to bite you. I learned that the hard way. Don't repeat my mistakes if you're trying to learn networking. No detail is unimportant.

There's one more gap that I had to fill before I went back to my practice lab on sending DHCP across inter-vlans and that's DORA.


What is DORA? I'm glad you asked.


DHCP Dora process is handled by a SERVER called DHCP SERVER that dynamically distributes network configuration parameters, such as IP Addresses, gateways, ect. for clients. It is a standardized network protocol used on INTERNET PROTOCOL in the network.

Sound complicated? It's not. Here's how it works.


First the client PC sends out a Discovery Broadcast across the network to see if a DHCP Server is on the network.

Next the DHCP server sends back an Offer that includes the IP address, gateway, ect.

Next the client PC sends back a Request saying that he will take the IP address.

Next the DHCP server sends back an Acknowledgement saying "okay, you I'll make a note of your IP address and you can have this IP address for 4-days (or whatever)...known as the lease time.


Client --------> Discover
......................Offer<-----------Server -
Client --------> Request
......................Ack<-------------Server



I'll explain why these 4 packets are important in a later post.

I said I would explain why DORA is important.

This is a real problem that I run into and the reason I had to learn how DORA worked.

I had 2 networks. One network was divided by Router 1 and the other network was divided by Router 2. I had the DHCP server on network 1 and 2 PC's on Network 2. From Network 2 I could ping the DHCP server on the other network but DHCP would not work. Ever.


It didn't make sense. I could ping the DHCP server that was on the other network. Anyone know why it wouldn't work?



Answer: the first letter in DORA stands for DISCOVERY and that's a "broadcast signal. Routers do not like broadcast signals and will drop them every time thus it will never reach the DHCP server.

[BillyCarpenter]

Re: Need some advice on learning networking

I can't believe I'm about to say this but I'm thinking of getting my CCNA. I've checked into it. I can do an online course in a live classroom setting. It's a 180 day course. The cost is around $1000.00.

I looked at some of the practice labs that I will have to learn. I've already done a lot of them.


With all of that being said, I have absolutely no plan of networking for a living. I don't even know why I'm considering it other than I've become very interested in networking and I find it fascinating. And I consider it a challenge.

Also, I'd like to have some structure learning networking as I feel like I'm kind of all of the place.


Good idea? Bad idea? Any advice?


Thanks.


PS - If I decide to do this it will be a few months from now. I need to learn a little more before I take that step.

[slimslob]

Re: Need some advice on learning networking

I can't believe I'm about to say this but I'm thinking of getting my CCNA. I've checked into it. I can do an online course in a live classroom setting. It's a 180 day course. The cost is around $1000.00.

Does that cost include the price of taking the certification test or is that still extra?

[BillyCarpenter]

Re: Need some advice on learning networking

Does that cost include the price of taking the certification test or is that still extra?

The exam is extra.

[BillyCarpenter]

Re: Need some advice on learning networking

Setting up these network labs in Packet Tracer continues to expose my weaknesses. This time the weakness that was exposed was subnetting. A long time ago i peeked in on subnetting and it looked complicated as hell, so I left it alone and I've avoided it thus far.


What is subnetting? To put it simply, subnetting is the process of taking a network and dividing it up into smaller sections. But the IP addresses must be right. There can't be any mistakes.

I've spent a couple of hours on it and I think I have it down but it's a little fuzzy. I'm gonna spend the rest of the day on it and practice it over and over. Hopefully I can get it down.

[adecanmin]

Re: Need some advice on learning networking

The exam is extra.

That's a lot of money. Knowledge is a good thing. Hopefully you may be able to monetize it for all your efforts. A bunch of years ago I studied and passed a Microsoft certification on networks. I liked the fact at the time it was cheap $100 and it I could use it on a business card. I'm self employed so getting the certification didn't increase my pay. Maybe in your situation your boss will help defray some of the cost since you'll become more valuable to your employer.

[BillyCarpenter]

Re: Need some advice on learning networking

That's a lot of money. Knowledge is a good thing. Hopefully you may be able to monetize it for all your efforts. A bunch of years ago I studied and passed a Microsoft certification on networks. I liked the fact at the time it was cheap $100 and it I could use it on a business card. I'm self employed so getting the certification didn't increase my pay. Maybe in your situation your boss will help defray some of the cost since you'll become more valuable to your employer.

I'm self employed, also. Now days a person doesn't need to get certified to gain the knowledge. It's all out there on the internet. I think I may be able to leverage the CNNA certification into a way of picking up some work from existing clients on the copier side of the business. I've noticed that a lot of my clients aren't quite big enough to have an IT person so they outsource the work. I've referred many of my clients to one of my friends who does networking/computers. That's money that I could be making.

[adecanmin]

Re: Need some advice on learning networking

Good points. Domain networks are usually outsourced to a computer company. Workgroups are the ones that will get someone who works there who has a little network experience to take care of their network or the copier guy who knows networks. Back in the day running network cabling was a good business. I'm seeing more companies running their computers wirelessly. With everything going to the cloud both private and public. Are we going to need a cloud certification?

[BillyCarpenter]

Re: Need some advice on learning networking

I'm done with learning subnetting. It wasn't as difficult as I thought. I'll never look at IP addresses and subnets the same again.


There is a formula for finding your custom subnets.


Here it is:

1. Identify the class of the network.
2. Identify the network portion of the IP address from the host portion.
3. Apply default subnet mask.
4. Convert subnet to binary.
5. Use 2n -2 to determine custom subnet mask.
6. Determine LSB....it gives your 1st subnet and range.


I also learned the IP range for
Class A: 10.0.0.0 thru 10.255.255.255
Class B: 172.16.0.0 thru 172.31.255.255
Class C: 192.168.0.0 thru 192.168.255.255

And the subnet for
Class A: 255.0.0.0
Class B: 255.255.0.0
Class C: 255.255.255.0

[slimslob]

Re: Need some advice on learning networking

Sorry to do this to you Billy but there is a lot more to subnet masks than that. When you have some time start here. Subnetting a Class B network address - TechRepublic

Have a nice day.

[adecanmin]

Re: Need some advice on learning networking

Good stuff

[BillyCarpenter]

Re: Need some advice on learning networking

Sorry to do this to you Billy but there is a lot more to subnet masks than that. When you have some time start here. Subnetting a Class B network address - TechRepublic

Have a nice day.

I looked at one of the charts and if you use the formula that I posted, you'll come up with the same chart...how many custom subnet are possible, how many nodes per subnet, ect.


I looked at the article you posted briefly and it does break it down in ways that I haven't seen. I'll go over the info. more when I get time. Thanks.

EDIT: By the way, the steps that I posted are more involved than it looks on paper. To get a good understanding of it, the video is the only thing that can do it justice. It's a 4 part video. Here's the main one. See below:

[BillyCarpenter]

Re: Need some advice on learning networking

I should also add this:


Basically what the guy in the video is saying is if you're an IT professional and you're setting up a network, you need to determine how many networks you need. It's good idea to estimate on the high side to allow for future growth. From there, you can use his formula to determine every subnet and the starting and ending range for each custom subnet. And the number of nodes (clients) for each custom subnet range. You can carry this out unitl you run out of custom subnets that are possible. And that's a lot.

[BillyCarpenter]

Re: Need some advice on learning networking

I made a mistake on the IP Range for Class A, B,C networks. Here's the correct range. My apologies.

Class A

IP Range: 1.0.0.0 to 126.0.0.0
First octet value range from 1 to 127
Subnet Mask: 255.0.0.0 (8 bits)
Number of Networks: 126
Number of Hosts per Network: 16,777,214


Class B

Range: 128.0.0.0 to 191.255.0.0
First octet value range from 128 to 191
Subnet Mask: 255.255.0.0 (16 bits)
Number of Networks: 16,382
Number of Hosts per Network: 65,534

Class C

• Range: 192.0.0.0 to 223.255.255.0
  • First octet value range from 192 to 223
  
  
• Subnet Mask: 255.255.255.0 (24 bits)
• Number of Networks: 2,097,150
• Number of Hosts per Network: 254