IT Blogtorials

Fourth post in this NAT series is the 'NAT with route-maps'. In my opinion, using route-map to manipulate NAT is a fairly advanced t...

Third post in this NAT series is "Dynamic NAT with Port Address Translation". Port Address Translation (PAT) works by translating...

Second post in this NAT series is "Dynamic NAT without Port Address Translation". I will go more into detail about PAT in my next ...

In this series of NAT blogtorials, we will start with a simple static 1 to 1 NAT mapping. Consider the simple topology below and let's d...

Now let's get into decrypting ICMP packets between R1 and R2. First let's capture some packets between R1 and R2. Right cl...

We will split this blogtorial into 2 parts. Part 1 will concentrate on how to setup up the IPsec-manual tunnel and Part 2 will concentrate o...

In this blogtorial I will demonstrate how to decrypt IPsec packets on a VPN between a Linux machine and a Cisco router. We will be using the...

In this blogtorial we will see how ACLs are sequenced and how we can resequence if we need to. ACL's initially start with sequence numbe...

How to get default routes into OSPF routing domain? Well, there is really just about one way to do it. It is by using default-information or...

Recently, I was tasked with troubleshooting a weird problem where one of the interfaces was err-disabled. Fun Monday mornings :) and siftin...

There are 4 ways to get default routes into EIGRP topology. We will take a look at all of them. Consider a simple 2 router topology and let...

In general, most ISPs will assign a /30 on point-to-point interfaces which gives you 4 IP addresses and 2 of which are usable resulting in 5...

The sooner we detect OSPF neighbor failure the faster the network can converge when there is a failure. In this blogtorial we will see how w...

Following from my previous  redistribution post . Let's explore a few ways we can prevent sub-optimal routing from redistributing routes...