Study notes for the Cisco CCNP exam
I’ve done a bit of work on NAT lately:
NAT Overview
NAT
ip nat outside source
I’m just going to finish up with the use of a route-map in NAT instead of the traditional access-list.
As an administrative note, while adding new contact information on the lower right (Skype and AIM), I noticed that my email address had the wrong [...]
Continuing on with the last article on NAT, I’m going to look at the ip nat outside source command.
The network in question is:
Bob is on the outside, and r1 is on the inside. I’d like R1 to connect to bob using the address of 5.5.5.5. That means an inside host will be using [...]
Getting back into things, I thought I’d do some practical work with NAT. I’ll go over the basic source NAT with overload, and then allowing an inside server to be accessed on the outside.
First, pinging the server from R1 times out. Looking at it from the server (Bob):
[root@bob ~]# tcpdump icmp
tcpdump: verbose output [...]
While Network Address Translation, or NAT, doesn’t appear on the exam outline, I have heard from several sources that it appears on the composite exam. It’s also one of those topics that I’d expect to be tested on in the simulator.
NAT is conceptually pretty easy — you’re manipulating addresses and possibly ports in order [...]
I was going to start into BGP, but realized that I’d have to take a diversion into policy-maps at some point. Since policy routing is on the exam, I think this is a much better place to start.
Identify the steps to configure policy-based routing using route maps
It’s likely that your first exposure to the [...]
In the last article about EIGRP, I’ll go over some of the show and debug commands relevant to the operation of EIGRP.
Show the established neighbours:
r0#show ip eigrp neighbors
IP-EIGRP neighbors for process 1
H Address Interface Hold [...]
There are many things that can be done to alter the behaviour of EIGRP. As we saw before, delay can be changed to make one link look worse than the other. Likewise, bandwidth can be changed, but since EIGRP uses the lowest bandwidth and the sum of delays, it makes more sense to [...]
When talking about DUAL, the stuck in active problem often comes up.
One of the final things I showed in the last article was the behaviour of a router trying to find a lost route when there was no successor. The router “went active” on the route to find a new successor. Cisco has [...]
EIGRP is easy to configure, but has a lot of options and can end up being very complex. Keep in mind that even though it looks and feels like a link state protocol, it is a distance vector protocol.
Here’s the network for the next few examples (pardon the hand drawing):
In addition, R2 and R4 [...]
Continuing on with the EIGRP articles, I’ll look at the EIGRP metric calculation.
EIGRP uses a composite metric, meaning it’s made up of several smaller metrics:
Bandwidth (minimum along path)
Delay (cumulative along path)
Reliability
Load
MTU
A good way to remember them is Big Dogs Really Like Me. These correspond to numbers that come from the show interface command, and [...]
