Category: Routing
Cisco IOS Flexible NetFlow
Browsing through the Cisco White Papers I stumbled on a new white paper about Flexible NetFlow. According to the white paper, Flexible NetFlow provides enhanced optimization of the network infrastructure, reduces costs, and improves capacity planning and security detection beyond other flow based technologies available today. Key Advantages to using Flexible NetFlow: Flexibility, scalability, aggregation … Read More
Configuration Example, Routing, Security, Switching
Secure HSRP configuration
A friend of mine works for a well known auditing and penetration testing company in the Netherlands. Recently we were talking about how he starts looking for flaws in network infrastructures. My friend told me that the first thing he does is simply starting WireShark and start looking at all the packets he receives. By … Read More
Configuration Example, Routing
Policy-Based Routing Catalyst 3560
Today I visited a customer where the power a Cisco Catalyst 3548XL blew up. The switch had a manufacture date of December 2000. It is an old one, but still I haven’t seen a power supply being blown up from a Cisco switch from that age. But oké, the switch needed to be replaced. The … Read More
Troubleshooting EIGRP
To troubleshoot EIGRP you should obvious have a grasp understanding of the specific routing protocol. Of course this doesn’t only apply to the EIGRP routing protocol. Troubleshooting the EIGRP routing protocol on a Cisco devices is mainly about logging the correct information to a syslog server, the buffer or the console and know what the … Read More
Change ESX host IP address
Monday I had to migrate an existing network. I added more VLAN’s to the network for segmentation and breaking the broadcast domain. I introduced a regular VLAN, a VoIP VLAN and a management VLAN. So far no problem. The customer is using Cisco Catalyst 3750G and Cisco Catalyst 3560 switches with PoE. I configured the … Read More
Configuration Example, Routing
BGP Multihoming
Today I have been playing with configuring BGP and multihoming. I configured a simple test environment where one customer router (local AS 100) connects to two ISP routers from the same ISP (remote AS 200). I configure some kind of load-sharing amongst the two links to the ISP. Important when configuring BGP is the concept … Read More