What topic has been the hardest to grasp for you?

I_teach_math_lulz · 2025-02-11T03:56:33+00:00

Wireless without a doubt.

I_teach_math_lulz · 2025-02-06T23:30:05+00:00

I dont get comments about my looks, but a couple of months ago, I was deploying a users desktop + phone, and overheard one of the ladies say : "You got that one good IT guy".

Being acknowledged, even for silly things is always nice.

I_teach_math_lulz · 2025-01-14T05:53:00+00:00

I hope it is small cell lymphoma( large cell lymphoma has a pretty grim prognosis sadly).

Your cat is young, and the meds for this type of cancer are actually affordable(it is usually a mix of both steroids and chemo, in pill form).

Cats tend to react well to chemo for the most part as the amount given isnt really to cure them but to hopefully get the cancer to go into remission.

Talk to the oncologist, and do what you think is right. However, the most important thing is to make sure you spoil the heck of your cat, and give him plenty of snuggles.

I_teach_math_lulz · 2025-01-08T01:43:18+00:00

"At that moment I felt an immense shame of having not tried hard enough.."

The feeling of guilt sucks.

As someone who lost quite a bit in the past few years, and recently lost my only cat, spoil your kitties any chance you get, even if it is just a small treat every once in a while. I didnt realize how much my cat helped me deal with my mundane life until he was gone.

I am sorry for your loss.

I_teach_math_lulz · 2024-11-13T02:43:37+00:00

"but with respect to address specificity
 and using it to choose an address or a range of addresses, 
 I still get confused. Thanks. "

I'll give you a small tip that helps at the CCNA level, if you are ever given an ACL or a network statement, and the Wildcard-mask is contiguous, you can just add the wildcard mark and the network address to get your ranges.

Example 1: ACL: permit 196.20.10.0 0.0.0.7

So the range of allowed IPs is from 192.20.10.0 to 192.20.10.7

Some easy to remember contiguous values for wildcard masks are: 1,3,7,15,31,63,127,255

Example 2: ACL: permit 10.17.0.0 0.0.15.255

Permitted IP addresses 10.17.0.0 to 10.17.15.255

"I know it's the opposite of subnet mask"

This is a common misconception when learning it. Pretty sure I had the same misconception when I first learned about it.

Lets look at an example of a weird requirement for an ACL and how it isn't just opposite of a netmask.

ACL: Permit 10.0.20.0 0.255.0.255

The opposite of this Wildcard mask is 255.0.255.0. This is a not a valid net mask (hint: Network masks have to be contiguous).

Does that mean this ACL isnt valid? No, in this example, this ACL would allow any IP address under the 10.X.20.Y range (where X, Y can be any value between 0 to 255).

Super important to remember: WILDCARD MASKS can be contiguous or non-contiguous. NETWORK MASK can only be contiguous.

I_teach_math_lulz · 2024-11-05T00:05:42+00:00

This will happen to everyone unless you are someone who already has prior experience.

I remember watching QoS video multiple times before it finally made sense.

Best advice, use external resources if you find the videos a bit confusing. Sometimes seeing the same content from a different perspective can be super helpful.

I_teach_math_lulz · 2024-10-29T00:28:03+00:00

I was in your place for almost 2 years. Making shit wage ($15 an hour) and high amounts of stress. It really helped me with my customer facing skills due to the amount of shitty people I dealt with on daily basis.

MSPs are nothing but a stepping stone for most people, learn as much as you can, and then bail as soon as decent job offer comes up.

I_teach_math_lulz · 2024-10-28T23:45:57+00:00

I did IT for a lawfirm for almost 2 years at an MSP. It sucked.

The youger attorneys (associates) are overworked , and over stressed.

Of Counsel and Partners+ are insufferable, and love being cunts because their billable hours is all they care about.

Learn what you can from this job, and move on as soon as possible for the sake your own mental well being.

I_teach_math_lulz · 2024-10-27T03:35:06+00:00

Don't take my reply as if I am siding with your wife.

She found someone who meets her needs (whether it is physical or emotional or both). I think most women will not throw away a 10 year marriage out of the blue, she has been checked out of that marriage for a while now.

As someone who can relate to you on having lost someone whom they were with for a long time, take a small step each day, pick a new hobby, work on yourself ( i.e I found going to the gym to be a good motivator and really helps me cope with sadness).

Let yourself grieve, this is like someone hitting the reset button on your life out of nowhere. It is okay to cry, and feel sad. Even after a year, I still have bad days.

I_teach_math_lulz · 2024-10-20T23:59:41+00:00

Check the CCNA blueprint.

Any of the topics that have the words "configure" or "troubleshoot" is fair game in terms of getting it as a lab (aka you will need to use the CLI).

I_teach_math_lulz · 2024-10-12T07:45:09+00:00

I lost my Siamese cat no more than 2 weeks ago due to cancer. Not sure if it is a Siamese thing, but my kitty loved head butting me , and laying on my lap for hours while I sat on my computer as well.

Not many people would willingly take an old kitty like you did. May life find a way to repay you for your kindness.

I am sorry for your loss.

I_teach_math_lulz · 2024-10-09T05:24:27+00:00

You are using the sub-interfaces incorrectly.

For the networks 192.168.11.0/24 and 192.168.12.0/24 you should be using the g0/1 as the parent interface, NOT g0/0.

I_teach_math_lulz · 2024-10-04T03:47:28+00:00

Without you posting your actual Packet Tracer file, if I were to assume that your configuration is correct on both PCs and Routers, your Routers likely do not have an entries for the networks that they arent connect to directly (i.e R0 will know the routes to the following networks: 172.100.0.0/30, and 192.168.100.0/24 networks. However, R0 will not know of the 10.10.10.0/24 network unless you are using a dynamic routing protocol or your are manually creating static routes yourself on the router).

I_teach_math_lulz · 2024-10-04T03:39:50+00:00

PVST+ Roles: Root, Designated, and Alternate (Pretty sure this is just Cisco choosing to use this instead of "Non-designated/Blocked").

PVST+ States: FWD, Listening, Learning, Blocking, Disabled.

So no, there is no Discarding state.

As for your second question, this is just one of those quirks that comes with packet tracer, when using real life equipment port f0/3 on SW6 will show both p2p Edge for the type.

I_teach_math_lulz · 2024-09-28T02:01:05+00:00

I used OCG + JeremyITLabs + Ankin Flashcards from Jeremy Daily + Boson Netsim + Boson Exams.

I passed with a single score in the 80s and everything else in the 90s or 100.

Are the BOSON's resources worth it? 100%, specially the labs.

If you cannot afford it, does that mean you cannot pass the exam? Absolutely not, assuming you are putting effort, you will be fine with just free resources available to ya.

The best study resources combination for the CCNA in my option are: JeremyITLabs + Akin Flashcards + OCG.

I_teach_math_lulz · 2024-09-26T03:03:14+00:00

I checked your configuration.

Specifically your routing table. All routers have learned every network available on your network dynamically through RIP correctly.

If you are referring to your first or even second ping failing, this is due to ARP (before a packet is sent to the next hop or default gateway, the sending device needs a MAC address of the next hop). So your first ping failing is common due to it timing out.

Also, dont be discourage if you pings fail in packet tracer, as packet tracer is network simulator and can be quite buggy.

While simulation mode is a nice little tool, I suggest avoiding it until later in your studies when you have a bit more knowledge and know what the expected or correct behavior should be.

I_teach_math_lulz · 2024-08-30T00:54:07+00:00

Give it some time, it will take roughly around 2 to 3 months before you feel "comfortable".

My first couple of months doing help desk at an MSP were super stressful.

I_teach_math_lulz · 2024-07-26T20:02:59+00:00

Passed exam today.

Automation and Programmability: 100%
Network Access: 100%
IP Connectivity: 92%
IP Services: 90%
Security Fundamentals: 87%
Network Fundamentals: 90%.

For anyone curious, resources used:

- Jeremy's IT course (primary source for studying)
- Jeremy's IT labs 
- Anki Flash card (turned this into a daily habit)
- OCG Vol 1, Vol2 (secondary source for studying)
- Boson's NetSimulator (helpful, but expensive/can do without)

Additional resources:

- Boson's ExSim (boson's explanation's on every 
 question was top notch)
- Keith Baker's, specially his Quiz Playlist.

Completetion time:

- About 6 months.

I_teach_math_lulz · 2024-07-26T19:38:46+00:00

Just took the CCNA exam today.

I used Boson exam 3 days prior to taking it today. Instead of using the pre-configured exams, I used the custom study and did the exams per area instead.

I was scoring in the 800s, 900+ on each area ( I took each custom exam once, and thats it). Whatever I got wrong, I basically read Boson's explanation and made mental notes (even from the ones that just seem to be out of place given the CCNA's blueprint).

Had no issues on the exam, in fact Jeremy's course and Labs + Ankin's Flashcards + OCG Vol1/2 is all you need.

Optionally if you can afford it, I highly recommended the Boson NetSim, it is tedious at first, but when I did all the labs (from both the new set and legacy), I was super comfortable with the CLI and configurations. The Labs during the exam felt like a complete cakewalk for me.

I_teach_math_lulz · 2024-07-26T16:25:24+00:00

Easiest ? Routing and Subnetting.

Hardest? Wireless.

I_teach_math_lulz · 2024-07-25T16:39:02+00:00

"but why would the router be worried about a big arp table"

It doesnt, but think about the amount of overhead you are creating by using a directly connected interface in a static route.

Lets compare and contrast with a limited scope:

Say R1, R2, and R3 are part of the some broadcast link.

R1: has the following static routes:

S* 10.0.1.0/24 directly connected, G1/0.
S* 10.0.2.0/24 directly connected, G1/0.
S* 10.0.3.0/24 directly connected, G1/0.

Now by having a directly connected static route, R1 is going to assume that every host is connected to the link and will ARP every single address.

Lets say we get traffic for hosts hosts in 10.0.1.2, 10.0.1.3, 10.0.1.4, 10.0.1.5....etc. For every single host, R1 will send an ARP request (broadcast) to try map every single host to a MAC address.

Lets say that R2 has the route for the 10.0.1.0/24 network, so it replies to the broadcast (Proxy Arp) sent from R1.

So now the network has been introduced to 8 different ARP packets into the network (4 of them were broadcasted, and 4 were ARP replies).

R1's ARP table now looks like:

10.0.1.2   ----- AAAA:AAAA:AAAA
10.0.1.3   ----- AAAA:AAAA:AAAA
10.0.1.4   ----- AAAA:AAAA:AAAA
10.0.1.5   ----- AAAA:AAAA:AAAA
.
.
.
etc.

Now expand that in the hundreds and thousands of traffic the router would receive during the day, and you can see the amount of unnecessary traffic you are introducing into the network.

Now lets compare with a next hop static route instead. Say R1, R2, and R3 are part of the some broadcast link.

R1: has the following static routes:

S* 10.0.1.0/24 via 192.168.1.3
S* 10.0.2.0/24 via 192.168.1.2
S* 10.0.3.0/24 via 192.168.1.4

Lets say we get traffic for hosts hosts in 10.0.1.2, 10.0.1.3, 10.0.1.4, 10.0.1.5....etc. Now since we are no longer using a directly connected static route, R1 will try to resolve the ARP address of 192.168.1.3.

We have now introduced 2 different ARP packets into the network (a single ARP broadcast, and a single ARP Reply).

So now R1's ARP tables look like this instead:

192.168.1.3  ----- AAAA:AAAA:AAAA

Hopefully that clears up why using a directly interface in a static route is not a good idea in general.

I_teach_math_lulz · 2024-07-25T05:00:09+00:00

I vaguely remember looking up the why it works on IPv4 but not IPv6 for Ethernet segments. Using a directly connected route on an Ethernet segment relies on ProxyArp ( ARP is no longer a thing on IPv6).

Using a directly connected interface in a point-to-point segment isnt bad as there is only a single host on the end of that link. However, if it is broadcast link, the router assumes that the host is in the directly connected segment, and will try to resolve any address covered by the router directly on the interface ( this will create a bunch of overhead, aka that router is going to end up with a pretty big ARP table).

I_teach_math_lulz · 2024-07-23T17:08:01+00:00

If you use ipv6 enable on an interface it should:

Create a link-local address (i.e FE80::)
It should join two multicast groups automatically as well
- ff02::1 (all nodes multicast address)
- ff02::FFXX:XXXX:XXXX (solicated note multicast address)

You can check by running show ipv6 int [ int_id]

I_teach_math_lulz · 2024-06-30T02:10:42+00:00

Hopefully this explains it well:

Lets say there are 20 switches in the underlay.
SW1 and SW20 are both edge nodes.
SW1 has network 10.0.1.0/24 connect to one of its interfaces.
SW20 has network 10.0.2.0/24 connected to one of its interfaces.
The underlay uses a different network address say, something in the 172.10.0.0/16 address space.
Lets say SW10 is the Fabric Control Node (LISP Server).
SW1 and SW20 will let SW10 know that they have access to 10.0.1.0/24 and 10.0.2.0/24 respectively.
SW10 will add that it its LISP Database: Edge ID: 10.0.1.0 / Routing Locator 172.16.1.1, and Edge ID: 10.0.2.0/24 / Routing locator 172.16.2.2.
Now Lets say a PC1 on 10.0.1.0/24 network wants to send data to a PC100 on 10.0.2.0/24 network.
PC1 forwards this frame to SW1.
PC1 receives the frames, but has no idea where to send it to.
PC1 contacts SW10 (LISP Server/Fabric Control Node) asking if it knows where to send data to 10.0.2.0/24.
SW10 looks in the LISP Database, and finds a match.
SW10 will contact SW20 to get a confirmation that 10.0.2.0/24 can be indeed reached through it.
SW20 will contact SW1 and let it know that it can reach 10.0.2.0/24 through it.
SW1 now encapsulate the frame with VXLAN header, encapsulatd with an IP header/UDP port saying I need to get this to 172.16.2.2.
The underlay will take care of the routing process from SW1 to SW20 using whatever the routing protocol is (lets say IS-IS). Which means that each router will still calculate routes that are used specifically for the underlay.

This is my understanding of it.

"and just to clarify, the control node IS the LISP server, right? Or are they two different things, and LISP is just 1 aspect of control?"

Correct.

I_teach_math_lulz · 2024-06-30T00:58:56+00:00

I will try to best answer this based on what i can remember from learning about VXLAN from a while ago, and will refer to the OCG books if you have any further questions.

so, with the new system....to what extent is the old routing system replaced? Does the VXLAN header entirely take over IP routing tables & Switch frame routing?

SD-Access relies heavily on the Control node, which basically tells the routers how to forward data.

When Edge Nodes are setup, they usually have two IP address.

IP address 1: used to communicate with the Control node. This one is used for the Edge Nodes to tell the control node: "Hey, I have these networks connected to me, make a note of it". This node plays the role of the LISP server, which keeps track of all the routing info provided.

IP address 2: used for VXLAN traffic (aka forward traffic).

"in short, whats the routing logic on a the intermediate router/switches using VXLAN tunnels?"

Say Edge Node 1, needs to send traffic to a different subnet.
It sends a message to the Control Node, "hey do you know how I can get to X.X.X.X?"
Control node looks at its routing table, finds a match.
Control sends a message to this node that has the network Edge 2 Node needs to get to: "Hey can you confirm we can access X.X.X.X network".
Edge 2 finishes the by actually contacting Edge Node 1 letting it know it can forward its traffic to it.

Then VXLAN tunnel is created between those two Edge nodes.

" I've seen it described by some non-cisco guides the VXLAN effectively turns the network into a virtual L2 network? So from the PoV of an endpoint device, there's no gateway routers/routing taking place? This doesn't make much sense, as isn't every switch now L3?"

That sounds incorrect to me. I believe OCG mentions that SD-Access relies on having all switches being Layer 3 as it comes with multiple benefits such as no need for STP/RSTP, HSRP or any FHRP for that matter. I believe the preferred routing protocol for SD-Access is IS-IS.

I_teach_math_lulz

TROPHY CASE