Need some advice on learning networking

[BillyCarpenter]

I spent the majority of the weekend learning about DHCP services across multiple vlans and it was one of the most confusing things I've run across thus far.


We need to keep this in mind: Every vlan is a separate broadcast domain...or network if you will. How do we get dhcp survives for every network? You could put a DCHP server on every network. That would get quite expensive. But that would be one way to solve the problem.

But what if we wanted one central DCHP server for all the VLANS. How would we do this? It took too many hours to get this down to where it's 2nd nature, but I finally got it.

I'll see if anyone can answer this question and I'll post my answer after enough time has passed.

[BillyCarpenter]

I spent the majority of the weekend learning about DHCP services across multiple vlans and it was one of the most confusing things I've run across thus far.


We need to keep this in mind: Every vlan is a separate broadcast domain...or network if you will. How do we get dhcp survives for every network? You could put a DCHP server on every network. That would get quite expensive. But that would be one way to solve the problem.

But what if we wanted one central DCHP server for all the VLANS. How would we do this? It took too many hours to get this down to where it's 2nd nature, but I finally got it.

I'll see if anyone can answer this question and I'll post my answer after enough time has passed.

Here's the answer. (see image below to look at the actual network setup)


In this particular lab, a layer 3 switch was used to create vlan10 &vlan20. A Cisco router is connected to vlan1 (default vlan). The Cisco router is the the DHCP server. Here's the problem....


The PC are on different vlans or networks if you will. The same is true for the Cisco router. Without making some changes, the PCs will not get a DHCP address.

Here's the solution. We must configure the Cisco router with 2 static routes. 1 will be for the network ID for Vlan10 and another static route for the network ID of VLAN20.

At this point the Cisco router will be able to ping VLAN 10 and 20, BUT DHCP still won't work. Why? Because when a PC sends out a DHCP request...it's a broadcast signal. Routers don't like broadcast signals and will be dropped. We now must configure DHCP helper and I won't go into that.



PS - Creating static routes blows and it's very time consuming and can get extremely complicated. There are much simpler ways of creating routes dynamically either by using RIP or OSPF. But in this course they want us to learn how to do it the hard way before using RIP or OSPF. It's a real bitch.

See image:

dhcp2112.JPG

[BillyCarpenter]

Quick comment on Layer 3 switches...

Thus far I've mainly used a layer 3 ROUTER. Well, I've made it to the part of the course that deals with layer 3 switches. Let me tell you something...they're simple if you need to create some vlans or do inter vlan routing. Both take mere minutes to configure.

However, if you need to go outside of that layer 3 switch, it gets really confusing, really fast.

When we're dealing with a layer 3 switch, it has SOME routing capabilities but they're not PHYSICAL ports. They are logical routes. This is all done by the software of the operating system. There's nothing to visually see like on a regular router. Anyway, I won't go into a big long story, but it takes some getting used to.

[rthonpm]

Ahh, welcome to the wonderful and exciting world of software defined networking.

You're really making me glad I don't deal with anything past the server. DHCP? DNS? Easy! Making it all work outside of the server room? That's someone else's problem.

Sent from my BlackBerry using Tapatalk

[BillyCarpenter]

Ahh, welcome to the wonderful and exciting world of software defined networking.

You're really making me glad I don't deal with anything past the server. DHCP? DNS? Easy! Making it all work outside of the server room? That's someone else's problem.

Sent from my BlackBerry using Tapatalk

I hear ya!!!

I think you had it right when you said that this is a specialty field. You're so right about it being software defined networking. Even on the regular Cisco routers, we are programing them to do what the job calls for. I look at it as playing the world's hardest video game. It's definitely different.

How well do you know Windows Server 2019? Or 2016? I'm running 2019 on a virtual box and I love it. Everything I've learned about it has been on my own, but if I can ever get thru this networking course, I'm jumping straight into another course on Server 2019. It's a hell of a lot more fun.

[rthonpm]

How well do you know Windows Server 2019?

2019 is all we're deploying for customers now, and by the end of the summer I hope to have all of our company Windows servers over to it as well. I've even gotten to the point where I'm doing just about all of them as server core to make the installs even smaller. I've had experience with the server side of Windows going back to Server 2000, though 2003 R2 was my first full-time work with a server OS.

[BillyCarpenter]

I really haven't looked at what lies ahead in the CCNA course. I've only concentrated on the task at hand. Well, I looked to see what lies ahead and it hit me that this is very serious course on networking. Basically, we're using a simulation program by Cisco that's running their software, so it's just like you're configuring the real thing when it comes to switches and routers.

When I say it's a serious networking course, what I mean is that down the road I'm gonna have to build "College Campus Network" and it looks plenty complicated. Oh, well, I'll worry about it when I get there.


On another note...right now I'm learning about broadcast and collision domains. Quick question? What has more collusion domains...a hub or a switch? Don't google it.

[BillyCarpenter]

Quick question? What has more collusion domains...a hub or a switch? Don't google it.

Answer: A switch has more collision domains than a hub. Confused? I was too. lol


Collision domains sound like a bad thing, right? Actually, the more on the network, the better. This video explains it better than i can. But think of it as lanes on a freeway. The more lanes, the more room for traffic. See video below:

[BillyCarpenter]

I have a customer that is using Windows Server 2019. Active Directory is not installed and needs to be. Here's my dilemma. When I join a local user to active directory, I need to migrate his/her user profile along with all their data to the new active directory account. I combed the internet for a solution but a lot of it looked complicated. What's the best way to do this?

Thanks in advance.


PS - I'm doing this as a favor so it's not critical. I told him I'd only check into it.

[slimslob]

I have a customer that is using Windows Server 2019. Active Directory is not installed and needs to be. Here's my dilemma. When I join a local user to active directory, I need to migrate his/her user profile along with all their data to the new active directory account. I combed the internet for a solution but a lot of it looked complicated. What's the best way to do this?

Thanks in advance.


PS - I'm doing this as a favor so it's not critical. I told him I'd only check into it.

Thus might help. Import Users Into Active Directory From CSV – TheITBros