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Routing

How to find out EIGRP Release Version

As some feature on the EIGRP can be limited to the version of EIGRP you are running on the router. This can be determined by using the command show eigrp plugins EIGRP Plugin Info R1#show eigrp plugins EIGRP feature plugins::: eigrp-release : 10.00.00 : Portable EIGRP Release : 1.00.08 : Source Component Release(rel10) parser : 2.02.00 : EIGRP Parser Support igrp2 : 2.00.00 : Reliable Transport/Dual Database manet : 3.00.00 : Mobile ad-hoc network (MANET) bfd : 2.00.00 : BFD Platform Support eigrp-pfr : 1.00.01 : Performance Routing Support EVN/vNets : 1.00.00 : Easy Virtual Network (EVN/vNets) ipv4-af : 2.01.01 : Routing Protocol Support ipv4-sf : 1.02.00 : Service Distribution Support ipv6-af : 2.01.01 : Routing Protocol Support ipv6-sf : 2.01.00 : Service Distribution Support vNets-parse : 1.00.00 : EIGRP vNets Parse Support snmp-agent : 1.01.01 : SNMP/SNMPv2 Agent Support R1#

Fine-tuning BGP Client / Server Relationship

Before you read through this post, I assume you have got at least the basic understanding of BGP and how it works.

Here are some facts…

BGP is a path vector Routing Protocol works on TCP port 179.

Neighbor with the lowers IP address will establish the connection to the Remote Peer on TCP port 179 with a random source port.

In this case, the Remote Peer will become the Server and the Local Peer will become the client. This peering relationship will change when we clear the BGP process on either peer or the underlying BGP connection get severed for any reason.

In case you want to specifically want to set one Peer as the Server and one as the Client, the IOS does support it.

This is how it is done…

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BGP Peer Templates

I have came across a lot of BGP configurations where there are lot of the configurations can be optimized. But having said that, this is not always the case when the Network is being built gradually.

Here is a couple of them, called Peer Session Templates and Peer Policy Templates; which we can use in such BGP configuration optimisations, when we…

  1. Design a Network from scratch.
  2. Design with a future overview.

These configurations can be used when it comes to commands which are session specific.

  • description
  • disable-connected-check
  • ebgp-multihop
  • exit peer-session
  • inherit peer-session
  • local-as
  • password
  • remote-as
  • shutdown
  • timers
  • translate-update
  • update-source
  • version

I wouldn’t personally set password on a template, because…

  1. You might want to have a different password for a specific peer because it is controlled by some other Administrative body.
  2. In my opinion, it is best practice to set the password per peer than to have it under a template.

Here is an example configuration from Cisco and also take a look at the Peer Policy Templates which is used under address-family. I would strongly advise you to read through the whole document.

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OSPF Loopback Interface

OSPF Loopback interfaces are treated as a stub host and will only have a 32 bit host route on the other devices no matter how the subnet mask is entered under the OSPF network statement.

We will explore how we can disable this default behaviour using a few methods.

ospf-loop

As you can see, R4 is configured with IP address 192.168.1.4 and R5 with 192.168.1.5.

We have loopback interfaces added with /24 subnet masks on R4 and R5

R4#sh run int loop0
Building configuration...
Current configuration : 61 bytes
!
interface Loopback0
ip address 4.4.4.4 255.255.255.0
end
R4#

R5#sh run int loop 0
Building configuration...
Current configuration : 61 bytes
!
interface Loopback0
ip address 5.5.5.5 255.255.255.0
end
R5#

We are running basic OSPF Configs as follows…

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Convert IPv4 into IPv6

I was going through 6to4 tunnel configs and thought I’d post some info on converting IPv4 address into IPv6 Address. This is pretty straight forward and its obviously involves HEX conversion. Method 1 (Please also see Method 2 below as I think it is much more easier) Here, I will convert the address 192.168.25.234 First we divide each octet by 16 and write down the remainder, primary school maths! 🙂 192 ÷ 16 = 12 remainder 0 168 ÷ 16 = 10 remainder 8 25 ÷ 16 = 1 remainder 9 234 ÷ 16 = 14 remainder 10 We also know that HEX has the following Values A = 10 B = 11 C = 12 D = 13 E = 14 F = 15 So we can write 192.168.25.234 into HEX like so… C0A8:19EA Now we will change the HEX Address C0A8:19EA into regular IPv4 C0 = (12 x 16) + 0 = 192 Read more

BGP no-export vs local-as

This is one of the BGP configuration I have came across on my lab… no-export : This will keep the route inside the confederation, but not to any peers. local-as : This will keep the route inside the AS, but not even to confederation peers. no-export –> local-as –> no-advertise If there is no confederation present, no-export will reflect the same result as local-as.