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Posts tagged CCNP
Policy-Based Routing Tutorial
Nov 18th
A friend asked me how to implement Policy-Based Routing (PBR) yesterday, after explaining it to him I thought it’d be nice to write a quick tutorial on here. PBR allows you to change a packet’s path based on different criteria. In this post I will use my friend’s scenario. We have a business with two internet connections, the powers that be have decided to use ISP B for all outbound SMTP traffic. Here’s our topology:
Let’s go through the config:
R1
hostname R1 ! ip access-list ext MATCH_SMTP 10 permit tcp 192.168.1.0 0.0.0.255 any eq 25 20 deny ip any any ! route-map SMTP_ISPB permit 10 match ip address MATCH_SMTP set ip next-hop 67.92.18.1 ! interface fa0/1 ip add 192.168.1.1 255.255.255.0 ip policy route-map SMTP_ISPB |
First we create our ACL that matches outgoing SMTP traffic, then we match the ACL in a route-map. After we match the traffic, we enter our action statement, “set ip next hop”. This route-map changes the next hope of all outgoing SMTP traffic. Finally we configure it on the LAN interface.
Free Cisco Lab
Nov 14th
Strech, the owner of PacketLife is now offering lab time for free. From his site:
Lab gear is broken into multiple “device blocks” to allow for multiple users to use independent portions of the lab simultaneously. Users can reserve one, several, or all of these blocks at once (however, a user may only have one unexpired reservation at any given time).
Block A
* 1x Cisco 2811 (with 2x WIC-2T)
* 2x Cisco 1841 (with 1x WIC-2T)
* 1x Cisco Catalyst 3550-24
* 1x Cisco Catalyst 3550-24 (with Inline Power)
* 1x Cisco ASA 5505
Block B
* 1x Cisco 2811 (with 2x WIC-2T)
* 2x Cisco 1841 (with 1x WIC-2T)
* 1x Cisco Catalyst 3550-24
* 1x Cisco Catalyst 3550-24 (with Inline Power)
BGP Backdoor Lab
Nov 12th
In this article we’ll be going over the BGP Backdoor feature. This is used in cases where two systems are connected via an IGP, but also receiving routes to the same system through BGP. I stumbled across this feature while checking out one of the labs on Darren’s Blog. The only way I could think of to complete one of his criteria was changing the Administrative Distance of either BGP or the IGP. That is essentially what this feature does, but on a route-by-route basis instead of changing the AD of an entire protocol. I asked Darren if that was the only solution and he pointed me to “BGP Backdoor”. As usual, I will be including my Dynagen/GNS3 .net file at the end of this post. Here is our topology:
Let’s go through the config:
R1
hostname R1 ! interface Serial0/0 ip address 10.1.1.1 255.255.255.0 ! interface Serial0/1 ip address 10.1.3.1 255.255.255.0 ! router bgp 65000 no synchronization bgp log-neighbor-changes neighbor 10.1.1.2 remote-as 65525 neighbor 10.1.3.2 remote-as 65535 no auto-summary |
OSPF LSA Types
Nov 4th
I can never seem to remember OSPF LSA Types for very long. I can cram them into my head for exams, but a week or so later they’re gone completely. I found a table from Internetwork Expert that is very, very helpful. I’m posting it here so I always have a copy and also in hopes that other people will find it useful as well.
(click image for fullsize)
EtherChannel Tutorial
Sep 11th
In this short article we will configure some Layer 2 EtherChannel links. These are used to aggregate switchports to increase bandwidth and provide redundancy. I am running a four port EtherChannel from my Edge router to my Core switch. This article is useful for CCNP (BCMSN) studies.
First we will configure our switchports, then we will configure the Port-Channel interface, then we’ll look at some show commands.
Here is the switchport configuration:
interface range GigabitEthernet0/23 - 26 switchport trunk encapsulation dot1q switchport trunk native vlan 10 switchport mode trunk channel-group 1 mode on |
We’ve set the trunking encapsulation to 802.1q and turn trunking on, then we set the native VLAN (I use 10), the command to note is “channel-group”, we have made the group 1 and set the mode to “on”, this means the port will not negotiate to become an EtherChannel, it just is.
Next we configure the Port-Channel interface:
interface Port-channel1 switchport trunk encapsulation dot1q switchport trunk native vlan 10 switchport mode trunk |
This is just a logical interface (somewhat similar to a Loopback). We do the same trunk configuration here.
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