This example shows how to generate 254 loop interfaces with assigned ipv4 addresses 172.16.0.1/24 up to 172.16.255.1/24. The code is: enable tclsh for {set i 0} {$i < 256} {incr i} { ios_config „int loop $i“ „ip address 172.16.$i.1 255.255.255.0″…

We investigate a special topology condition, where a switch is connected itself on ports Faa0/1 and Fa0/2, and one of the port has BPDUFilter feature applied (i.e. simulating STP is switched off). Both ports are in the same vlan (vlan…

There is some confusion and misunderstanding regarding VTP (VLAN Trunking Protocol)+DTP (Dynamic Trunking Protocol) and this article will hopefully make it all clear. Most of the confusion comes from the statement that VTP is always a security threat to your…

Notes: Loki is a Python based framework implementing many packet generation and attack modules for Layer 3 protocols, including BGP, LDP, OSPF, VRRP and quite a few others. Web: https://www.c0decafe.de/loki.html http://www.ernw.de/content/e6/e180/e1561/Blackhat2010_ERNW_Loki_ger.pdf http://www.ernw.de/content/e6/e180/index_eng.html http://www.packetstan.com/2011/02/running-loki-on-backtrack-4-r2.html

A simple comparison of the nslookup command, the Microsoft DNS tool, and dig, the linux/win based command alternative. How to find the root servers? Using nslookup using dig  C:\Users\palo>nslookup Default Server: iris.isp.kx.sk Address: 85.248.45.238> set type=ns > . Server: iris.isp.kx.sk…

In this article I will configure reflexive ACL. This technique is described during CCNA4 Exploration, and I'm using it during the lab exercises. Description from the cisco web, regarding IOS 15.1.

The flash animation explains how to configure DHCP server on a cisco router using the SDM. Where to find and how to install the SDM is described in this article.  

Sometimes in my lab happens that students delete IOS of the switch from its flash. Unfortunately switches does not have rommon to realize quick IOS recovery over tftp. Only one way is over Xmodem. To speed up the process of…

In this article I will configure dynamic complex ACL (Lock and Key). This technique is described during CCNA4 Exploration. Description from the cisco web Lock-and-key is a traffic filtering security feature that dynamically filters IP protocol traffic. Lock-and-key is using…

In this article I will configure, debug and shows the process of RIPv2 authentication.   Authentication methods Plain text MD5   Note 1: When using plain text authentication mode, make sure that the following parameters are matching on neighboring routers…