Need some advice on learning networking

[BillyCarpenter]

I was laid off for about a year and a half, and had all kinds of time on my paws.

Now I’m back to workin’ for the man, and my spare time is scarce again.

Gotta say…It feels really good to be back at work. And as Joni Mitchell so elegantly put it, “Don’t it always seem to go, that you don’t know what you got ‘til it’s gone”. Couldn’t be more true!

Glad that you're working again. But you better find some time to post on here.

[BillyCarpenter]

Mastering the "life of a packet" is proving to be more difficult than it first appeared. I've found that most topics covered in the CCNA exam are intended to be analyzed and dissected from every angle.

For example: The "life of a packet" is basically teaching how to troubleshoot a network at the WireShark level.

What do you guys think about troubleshooting a network at the WireShark level? Necessary? Overkill?

I have my own thoughts and will share after we get some feedback on the question.

[BillyCarpenter]

Here's an interesting question for all you networkers:


How does your PC know how to contact the Default Gateway and can you explain the steps involved in doing so? As always...no using Google.

[BillyCarpenter]

Here's an interesting question for all you networkers:


How does your PC know how to contact the Default Gateway and can you explain the steps involved in doing so? As always...no using Google.

Instead of me explaining it, this is the instructor in one of the courses that I'm talking.

[BillyCarpenter]

Here's an interesting question for all you networkers:


How does your PC know how to contact the Default Gateway and can you explain the steps involved in doing so? As always...no using Google.

In easy to understand language, the PC knows it needs to connect to the default gateway only when it's trying to send a packet to a different network. Bascially what the PC does is compare the destination IP address with it's own address and if it's on a different subnet it knows to contact the default gateway.

There's only one small problem. The PC doesn't know the MAC Address of the default gateway. How does the PC find the MAC address of the default gateway? Hhhmmmm.....

[skynet]

How does the PC find the MAC address of the default gateway? Hhhmmmm.....

Arp?

[BillyCarpenter]

Arp?

Very good, skynet. That is correct. As I've been saying, ARP is the Rockstar of networking protocols. Or maybe a better analogy would be that ARP is the lead singer of a rock band??!!

In any event, before the day is done, the topic of moving a packet is gonna get much deeper and more complicated.

[BillyCarpenter]

Tracing a packet has taken me on an unexpected journey.


I think most people are familiar with the PING COMMAND. But I doubt too many fully understand it and could interpret it on WireShark. As I type this, I'm working to to fully understand it.

[skynet]

Very good, skynet. That is correct. As I've been saying, ARP is the Rockstar of networking protocols. Or maybe a better analogy would be that ARP is the lead singer of a rock band??!!

In any event, before the day is done, the topic of moving a packet is gonna get much deeper and more complicated.

Thanks that came from memory, I prefer short to the point video's, but then I ain't taking a networking course.
ARP Explained - Address Resolution Protocol - YouTube

[BillyCarpenter]

Thanks that came from memory, I prefer short to the point video's, but then I ain't taking a networking course.
ARP Explained - Address Resolution Protocol - YouTube

I watched the first couple of minutes of the video you linked to and it did a great job of explaining ARP.


But in the course I'm taking, I must observe ARP as a packet travels across routers and switches and that's where it gets tricky. Think of it like this: Routers are used to move data from one network to the other. Mac Addresses are used to move data to the "next hop". I'll explain more about it in a bit.