ACL

VMware NSX is something something awesome

At times I have trouble focusing on writing articles for some of the presentations I am exposed to at Tech Field Day. Because of that, I really wanted to try something different. …

AS-Path Filtering

Before we get into the how, let’s talk about the why. According to the CIDR Report, the global IPv4 routing table sits at about 525,000 routes, it has doubled in size since mid …

Using Deny ACEs in your PBR ACL on your Nexus 7k

Quite a while ago I had a need for some network duct tape… Policy Based Routing while useful should only IMHO be used as a temporary fix. But as you know, temporary things soon …

Time-based ACLs

Ever since Cisco released IOS 12.0.1T we’ve had the ability to broaden the reach of the extended ACL to allow the influence of time.

Using Discontiguous Wildcard Masks in ACLs

Unlike subnet masks, wildcard masks allow you to use discontiguous bits which enable you to match on a range of values. Using these within routing protocols is typically frowned …

IOS ACL Resequencing

This is one of those tricks you wish you learned about 10 years ago, but never did. You know how easy it is to mess up a nice looking access list. You get one setup on the router, …