VLAN Access Lists (VACLs)

VACLs are another good layer of security to help control who can talk to who, much like  access control lists that are in firewalls and routers, however the difference is VACLs operate at layer two of the OSI model. There could be situations where you have multiple hosts on the same LAN and want to block traffic from reaching certain hosts within that same network, how would you go about blocking that type of traffic without using a router or firewall? (Hint: Create a VACL)

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GLBP Load Balancing

We could use HSRP or VRRP to have a redundant default gateway for our PC/server networks. Although this works well we now have hardware powered-on and just sitting around waiting for its counterpart to fail, we are not actively using it. We could split up networks or use multiple default gateways within the same network but who does that? Well if your router or layer three switch happens to have that Cisco logo on it and a software release of at least 12.2(14)S, please welcome and “slow clap” the Gateway Load Balancing protocol, who has been around since 2002! Continue reading

Dynamic Routing Protocols

If you ever wanted to set up a network manually, you will quickly find how much overhead is required to get PCs, printers, and other network equipment. That’s where dynamic routing protocols come into play although they are helpful I strongly urge you to understand static routing first. (See the post Configure Static Routing) So for today’s post let’s get the foundation of understanding dynamic routing protocols. Continue reading

Configure Static Routing

Plugging Cisco routers together and hoping they work out of the box is not something you should hope for. A router can learn about networks in two ways, manually from configured static routers which we will talk about today and dynamic routing protocols which will talk about on Wednesday. Let’s get started! Continue reading