Have I talked about the Cisco Firewall Services Module (FWSM) before? It’s a firewall on a module for the 6500 and is based on the PIX firewall. The term “based on” is important here, since it does a lot of stuff the PIX does but…
Author: jac
Aaron does lots of stuff and, therefore, does nothing well. He's trying, though.
https://masto.ai/@aconaway
In my billion years in the industry, when I’ve asked for network diagrams, I’ve inevitably received a physical diagram — a diagram that shows where stuff is plugged in. This is fine and dandy and has lots of information, but that’s not really enough these…
Here’s a scenario I ran into long ago. We had several sites that had a frame relay link back to headquarters and a DSL line. Each link was terminated into a different router on a flat LAN with the users. The DSL was for Internet…
In my professional life at some point, I came across someone who had a stack of Catalyst 2950 switches all trunked together with their Internet routers connected to the top of the stack. This was all well and good until they kept adding hosts to…
If you’re running iBGP, you may have run across this. What if you had three routers — R0, R1, R2 — that were running BGP under the same ASN, but R1 and R2 weren’t peered? Any routes coming from R1 would not show up on…
VLAN Trunk Protocol (VTP) is a little gem on Cisco switches that allows you configure VLANs in one place and have them appear on all of your switches. This is great for large enterprises with 8457839 switches all trunked together because who wants to configure…
A lot of IOS commands give you a lot of information. Most of the time, though, it’s way too much information, and it sure would be nice to do some grep-like stuff on the output, right? Well, just like on Linux, you can use the…
I realized the other day that I haven’t mentioned EIGRP once. As a Cisco guy, I think I’m required to do at least one article on it, so here it goes. Enhanced Interior Gateway Routing Protocol (EIGRP) is a Cisco-proprietary routing protocol. Routing protocols share…
We just talked about tagging traffic and policing traffic, but we haven’t talked about prioritizing traffic. Tagging just sets a value in the header. Policing sets a “bandwidth ceiling” that can’t be crossed. Prioritization guarantees a certain amount of bandwidth for a flow/app/etc. no matter…
We covered QoS tagging the other day, but that just marks packets. I think you’re old enough now that we should actually do some policing. Policing is where you restrict the amount of bandwidth that a flow or set of flows can use. For example,…