Few will deny that monitoring of Cisco devices is essential part of sysadmin’s job. I personally use Nagios to track states of BGP neighbors on Cisco routers so if one of peers goes down I’ll receive a phone call from Nagios. You may have redundant network topology but it still makes sense to know when peer goes offline, how often it happens and how fast failover router (if any) pick-ups [...]Read more →
The Implementing Cisco IP Routing (CCNP Route 642-902). Materials for efficient preparation to the exam.
A few days ago I have successfully passed 642-902 exam (CCNP ROUTE v6) and would like to share the list of materials I have been using to prepare to that exam. To get prepared I was using official Cisco Press training resourses, lab simulations and cheat sheets (before actually to go an take the exam). In this post I’d like to share this staff with you. A few words about [...]Read more →
There is Cisco router of 7200 series with 4 FastEthernet interfaces (FE) and 2 serial ports. It should act as load balancer and failover for LAN connected to it via one FE 1/0 interface while two identical Internet connections are going to FE 0/0 and FE 0/1 (let’s name these connections as ISP_1 and ISP_2). No dynamic routing protocols are used by ISPs but only static routing. The primary task [...]Read more →
Using nfsen it is possible to view IP traffic statistics on Linux interfaces including the graphs showing data sent and received (see the screenshot to the right) as well as historical information about all data transfers. So after you’ve configured nfsen and nfdump to monitor traffic on certain Linux server or router you’ll be able to answer the following example questions: What IP was downloading data through 48161 last Wednesday? [...]Read more →
By default Cisco IOS doesn’t provide any traffic monitoring tools like iftop or iptraff available in Linux. While there are lots of proprietary solutions for this purpose including Cisco Netflow Collection, you are free to choose nfdump and nfsen open source software to monitor traffic of one or many Cisco routers and get detailed monitoring data through your Linux command line or as graphs at absolutely no cost. Below is [...]Read more →