We know that two OSPF routers will become neighbours if they can agree on certain parameters (see my previous post for details) and this is great, but suppose the bad guys were able to connect their own router to the same data link and then cause OSPF routing mayhem – how do we stop this??? […]
In this post we’re going to take a look at the process of two Cisco routers forming an OSPF neighbour adjacency, with an emphasis on what’s going on at a packet level. We’ll look at the packets sent and received on a multi-access network type, in this case Ethernet. Here’s our network: Our OSPF config […]
In my previous Junos Basics post I covered configuring a Juniper EX2200C switch as a DHCP server. In this post we’ll step through a really nice feature of Junos that is an absolute no-brainer – configuring your Juniper device to automatically back up a copy of it’s configuration file to an FTP server every time […]
In my previous Junos Basics post I covered a simple OSPF configuration in Junos. In this post I’ll step through configuring a Juniper EX2200C switch as a DHCP server. The EX2200C is a great little switch that’s ideal for a small branch office deployment, and one feature that you might look to take advantage of […]
In my previous Junos Basics post I covered a simple VRRP configuration in Junos. In this post I’ll run through a basic OSPF configuration on a pair of Juniper routers. Here’s our network: Objectives: Establish an OSPF neighbour relationship between R1 and R2 increase security by using md5 authentication Configure all router interfaces to be […]
In my previous Junos Basics post I covered aggregating ethernet interfaces using LACP on a Juniper switch. In this post I’ll cover a simple VRRP configuration in Junos that provides first hop router redundancy for clients on a local LAN segment. Here’s our network: Note – all routers are running OSPF, with both interfaces on […]
In my previous Junos Basics post I covered configuring an 802.1Q Trunk between a Juniper EX2200C and a Cisco 2960S. This post will expand upon the previous one by bundling two interfaces together on each switch to form an aggregated link for the trunk. There are a few proprietary standards for aggregating ethernet links, but […]
In my previous Junos Basics post I covered creating RVI’s to enable routing between different VLAN’s. In this post I’ll cover configuring an uplink port on an EX2200-C switch to trunk the VLAN’s out to an access layer switch – in this case a Cisco 2960S. This will also allow us to compare the trunk […]
There are many reasons why you would want to implement route filtering. A good example would be to prevent routes to transit networks being advertised to a branch router, because no host in the branch would ever need to send packets to a host in the transit network. Filtering in EIGRP is configured using the […]
In my previous Junos Basics post I covered the configuration steps required to create VLAN’s on a Juniper switch and assign interfaces to them. In this post I’ll step through the config to enable routing between these VLAN’s and also show a couple of verification commands to check it’s working as expected. Firstly we configure […]