Hey Guys,
I'm just thinking about going for my CCNA certification. Do you guys have any advice for me before I start to study? I've only setup a single switch before, but I've watched a network guy setup a VLAN, MTU size, port enabling, IP settings, console set up, ssh remote in, etc.
I've also recently applied for a network administration job which is way over my head, but I feel confident I can figure it out. I need to setup firewalls, which I've never done before. Humm... any advice, other than don't do it would be much appreciated.
-Myth
Here's a clue from an actual hiring manager: don't apply for a network administrator gig unless you are fairly solid in your network skills, because one of those things you would inevitably do is to fix problems in an emergency, and you don't want to be seen frantically looking for results on Google while your company's bottom line is at stake. Most network guys are there to do initial setups and to fix things during breakdowns/emergencies. It might be okay if you are a junior SA who is under the wing of someone more experienced and can teach you the stuff while on the job, but if you are the single point of contact when the proverbial hits the fan, well, you are going to be overwhelmed real quickly. Fake-it-'til-you-make-it is not a good idea here - it'll often lead to fake-it-and-you-broke-it.
Okay, as for certification - eh, I don't favor it since many of the CCNAs I interviewed are blithering idiots. They might know the 3 to 4 letter abbreviations or the 7 layer OSI cake (Aunt Patty Sells Taiwanese network dog poop), but they can't tell me why something was done, and what's the advantages of doing it in a certain way - like what does it mean to have a VLAN tag, and how switching decisions are done on the hardware level.
Instead of focusing on a specific certification program focusing on a specific vendor's specific take on technology, look at the generic/standard scenario out there, and work on things that lean to that. Yes, you should buy a switch or 2 (a Cisco Catalyst 3524 is worth nothing, and a Juniper EX4200-48 is only $100+shipping) , a router or 2 (you don't even need an expensive one - an EdgeRouter lite, a Mikrotik or even a cheap wireless router running DDWRT will do just fine), or maybe even VMs of routers and switches (hit up a network engineer for Cisco IOS VMs, Juniper JunOS / vSRX or even Arista for their vSwitch), but the challenge is to figure out how to interconnect them together using various means, and then figure out a way to monitor/troubleshoot them.
As you are going through, ask yourseld questions like -
- Can you find out what's connected on the other side of a switchport on a Cisco switch? How about a Juniper one?
- Do you need special equipment to connect Infiniband equipment to ethernet? Where would you see that in a data center?
- Why is it so important to disable spanning tree in certain situations on 100Mbit Full-duplex switches?
- What's the actual difference between a router and a switch, and why is the line between them often blurred?
- What's the industry standard for monitoring networking equipment, and how would it interface with the monitoring software?
- How would you backup your current settings and how would you restore it quickly in an emergency?
- How would you track changes made to equipment configuration files?
- What are some of the warning signs of a routing engine failure?