Passive-interface command behavior in RIP, EIGRP & OSPF

Passive-interface command is used in all routing protocols to disable sending updates out from a specific interface. However the command behavior varies from o­ne protocol to another.

In RIP this command will disable sending multicast updates via a specific interface but will allow listening to incoming updates from other RIP speaking neighbors.

This simply means that the router will still be able to receive updates o­n that passive interface and use them in the routing table.

In EIGRP the passive-interface command stops sending outgoing hello packets, hence the router can not form any neighbor relationship via the passive interface. This behavior stops both outgoing and incoming routing updates.

In OSPF the passive-interface has a similar behavior to EIGRP. The command suppresses hello packets and hence neighbor relationships.

Cisco Router - How to configure SSH

Below shows you how to enable SSH on your router using a username of "cisco" and a password of "network", allowing access from the fa0/0 interface.

Router(config)#ip ssh source-interface fastEthernet 0/0
Router(config)#ip ssh authentication-retries 3
Router(config)#ip ssh version 2

Router(config)#ip domain-name local.net
Router(config)#crypto key generate rsa modulus 768
Router(config)#username cisco password 7 network

Router(config)#line vty 0 15
Router(config-line)# transport input ssh
Router(config-line)# local login

Configuring the Cisco IDS Router / Switch Modules for Cisco 6500 Switch / 7200 Router

IDSM-2

The IDSM-2 Module is a Cisco IDS blade for the Cisco 6500 switch.
Once you install the module into the switch the module uses following logical ports :

Port 1	Used for TCP Resets (In Promiscuous Mode)
Port 2	Command and Control
Port 7	Sensing Port
Port 8	Sensing Port

Below details the steps required for configuring your switch / module for an inline setup. This includes obtaining the module number for the cisco ids running the setup wizard and then assigning the required ports for on the switch for ids sensing within an inline configuration. The clear trunk commands are required as by default the switch assigns the ports as trunk ports to every vlan.

How to configure a Cisco Layer 3 switch-InterVLAN Routing

Cisco Catalysts switches equipped with the Enhanced Multilayer Image (EMI) can work as Layer 3 devices with full routing capabilities. Example switch models that support layer 3 routing are the 3550, 3750, 3560 etc.

On a Layer3-capable switch, the port interfaces work as Layer 2 access ports by default, but you can also configure them as “Routed Ports” which act as normal router interfaces. That is, you can assign an IP address directly on the routed port. Moreover, you can configure also a Switch Vlan Interface (SVI) with the “interface vlan” command which acts as a virtual layer 3 interface on the Layer3 switch.

On this post I will describe a scenario with a Layer3 switch acting as “Inter Vlan Routing” device together with two Layer2 switches acting as closet access switches.

How to Configure a Cisco ASA 5510 Firewall – Basic Configuration Tutorial

This article gets back to the basics regarding Cisco ASA firewalls. I’m offering you here a basic configuration tutorial for the Cisco ASA 5510 security appliance. This device is the second model in the ASA series (ASA 5505, 5510, 5520 etc) and is fairly popular since is intended for small to medium enterprises. Like the smallest ASA 5505 model, the 5510 comes with two license options: The Base license and the Security Plus license. The second one (security plus) provides some performance and hardware enhancements over the base license, such as 130,000 Maximum firewall connections (instead of 50,000), 100 Maximum VLANs (instead of 50), Failover Redundancy, etc. Also, the security plus license enables two of the five firewall network ports to work as 10/100/1000 instead of only 10/100.

Next we will see a simple Internet Access scenario which will help us to understand the basic steps needed to setup an ASA 5510. Assume that we are assigned a static public IP address 100.100.100.1 from our ISP. Also, the internal LAN network belongs to subnet 192.168.10.0/24. Interface Ethernet0/0 will be connected to the outside (towards the ISP), and Ethernet0/1 will be connected to the Inside LAN switch. 

Different Types of Firewalls

Companies such as Cisco and other major vendors have introduced a multitude of firewall products that are capable of monitoring traffic using different techniques. Some of today's firewalls can inspect data packets up to Layer 4 (TCP layer). Others can inspect all layers (including the higher layers) and are referred to as deep packet firewalls. This section defines and explains these firewalls. 

The three types of inspection methodologies are as follows:

• Packet Filtering and Stateless Filtering.
• Stateful Filtering.
• Deep Packet Layer Inspection.

How to Configure DHCP on Cisco Router 871 or 18xx or 21xx or 26xx .(Series)

DHCP stands for Dynamic Host Configuration Protocol. Basically it’s a mechanism which assigns IP addresses to computers dynamically. Usually DHCP is a service running on a server machine in the network in order to assign dynamic IP addresses to hosts. All Cisco 800 series models have the ability to work as DHCP servers, thus assigning addresses to the internal LAN hosts. Without a DHCP server in the network, you would have to assign IP addresses manually to each host. These manually assigned addresses are also called “static IP addresses”.

How to Configure Cisco VTP – VLAN Trunk Protocol

In a previous post I explained how to configure VLANs on Cisco Switches. That was a simple scenario with just two switches connected with a trunk port and having shared VLANs belonging to both switches. Now, imagine the situation where you need to manage a huge Layer 2 switched network with tens or hundreds of switches and with VLANs spread across all switches in the network. This would be a daunting task for any network administrator as he would have to connect on all switches and add or remove VLANs accordingly every time a new vlan is required in the network.

How to Configure VLANs on a Cisco Switch (All Series)

This post will deal with configuring Layer 2 VLANs on Cisco switches. Up to 4094 VLANs can be configured on Cisco catalyst switches. By default, only VLAN 1 is configured on the switch, so if you connect hosts on an out-of-the-box switch they all belong to the same Layer 2 broadcast domain.

The need to configure several Layer 2 VLANs on a switch arises from the need to segment an internal Local Area Network (LAN) into different IP subnetworks. If you want for example to separate the different departments of your enterprise into different IP subnetworks, then each department should belong to its own Layer 2 VLAN.

OSPF - LSA Types ( 5 Types)

OSPF - LSA Types:

Type 1 - Sent by routers within the Area, including the list of directly attached links. Does not cross the ABR or ASBR.

CBT-Nugget - Netmaster Class Cisco Pix Adaptive Security

Netmaster Class Cisco Pic Adaptive Security CBT

Description:

The Cisco PIX Firewall and/or the Adaptive Security Appliance (ASA) are the cornerstone of the Cisco Self Defending Network. This training package allows you to master these key Cisco security technologies in the most efficient manner possible.

The LEARNiT: PIX/ASA package includes the following:

- Extremely detailed Reference Sheets explaining all major features of the products.

- Video-On-Demand recordings by NetMasterClass instructors.

- Practice Exam Database.

This course is recommended for the following IT Professionals:

• Those that want to master the PIX/ASA devices for network implementations.
• Those that want to obtain the CCSP Certification.
• Those that want to begin CCIE Security track preparation.

EBook - Cisco ASA: All-in-One Firewall, IPS, and VPN Adaptive Security Appliance (2nd Edition) - 2009

Cisco ASA: All-in-One Firewall, IPS, and VPN Adaptive Security Appliance

Cisco Press | ISBN: 1587058197 | Dec 29, 2009 | 1152 pages | PDF | 25.7 MB

For organizations of all sizes, the Cisco ASA product family offers powerful new tools for maximizing network security. "Cisco ASA: All-in-One Firewall, IPS, Anti-X and VPN Adaptive Security Appliance" Second Edition, is Cisco's authoritative practitioner's guide to planning, deploying, managing, and troubleshooting security with Cisco ASA.

Written by two leading Cisco security experts, this book presents each Cisco ASA solution in depth, offering comprehensive sample configurations, proven troubleshooting methodologies, and debugging examples. Readers will learn about the Cisco ASA Firewall solution and capabilities; secure configuration and troubleshooting of site-to-site and remote access VPNs;Intrusion Prevention System features built into Cisco ASA's Advanced Inspection and Prevention Security Services Module (AIP-SSM); and Anti-X features in the ASA Content Security and Control Security Services Module (CSC-SSM).

IP Helper Address Command for Router (Used in DHCP Broadcast)

BOOTP/DHCP Server – Port 67

BOOTP/DHCP Client – Port 68

Configure router to pass DHCP requests from local clients to a centralized DHCP server

The traditional role of routers in DHCP has been simply to act as a proxy device, forwarding information between the client and server. Since IOS level 12.0(1)T, Cisco routers also have DHCP server and client features. But the DHCP proxy function is still the most common for routers.

Because the initial DHCP request comes from a client that typically doesn’t have an IP address, it must find the server using a Layer 2 broadcast. So, if the router was not able to function as a proxy for these broadcasts, it would be necessary to put a DHCP server on every network segment.

Ways of InterVLAN Routing - Routing between VLAN Networks | Need Of VLAN Routing | Types of VLANs Routing

Introduction This article deals with the popular topic of InterVLAN routing, which is used to allow routing & communication between VLAN networks. Our article analyses InterVLAN routing and provides 4 different methods of InterVLAN routing to help understand the concept.

Using The Paessler PRTG Traffic Grapher In a Cisco Wide Area Application Services | PRTG Grapher for Cisco Router and Switches

About the PRTG Traffic Grapher

The PRTG Traffic Grapher is a Microsoft Windows software tool for monitoring and classifying traffic bandwidth use. It offers a simple, easy-to-learn interface and provides system administrators with live readings and long-term use trends for their network devices. The PRTG Traffic Grapher is most commonly used for bandwidth management, but its sensor technology can also be used to:

• Log the amount of data flowing in and out of Simple Network Management Protocol (SNMP)-enabled network components using the Internet MIB-2 standard.

• Inspect all data packets passing a computer's network interface card (packet sniffing).

• Incorporate bandwidth use data sent by Cisco routers using the NetFlow Version 5 protocol.

The packet sniffer and NetFlow-based monitoring capabilities of the PRTG Traffic Grapher provide the capability to classify traffic by protocol, IP address, and MAC address.

Cisco Packet Tracer 5.1 : Network Simulation Software

Packet Tracer 5.1

About Packet Tracer

Packet Tracer is a self-paced, visual, interactive teaching and learning tool. It is designed to increase interaction between students and instructors, promote student learning, and enhance instructor presentations. This technology is a new and fun way to expand teaching and learning experiences beyond the limitations of a traditional lab environment. Packet Tracer helps resolve some common challenges that instructors face on a daily basis, while enabling us to explore new frontiers in networking education.

Password Recovery on a Cisco Router

In this post I'll demonstrate how to perform password recovery on a Cisco router, and I'll also show you how to prevent password recovery.

Password recovery might be necessary for legtimate needs or it could be used by an attacker for nefarious purposes such as to gain access to router or switch configurations. Physical access is required for password recovery so if your routers (or switches) are in an accessible area and cannot be physically secured you may want to use the command listed below for preventing password recovery (if your router supports it that is).

Setting Up SSH on a Cisco Devices (Router and Switches,etc)

In this post I'll demonstrate how to configure SSH on a cisco router.

Below are the commands I used to name the router and provide a domain name. These details are required rior to generating the key. I then generate a 2048 bit RSA key (this took abolut 10 minutes, I should have done 1024). Following the key creation I configure SSH to have a 60 minute timeout, to use SSH version 2 and to exit after 3 failed login attempts. Finally I assign SSH and Telnet (for backup) to my VTY ports and create a user called XcessL.

Cisco Advanced CCIE Routing & Switching Workbook | Cisco INE CCIE Routing & Switching Advanced Technologies

Cisco Advanced CCIE R&S WorkBook | 351.66Mb

The CCIE Routing & Switching Advanced Technologies Class is the first step in understanding CCIE level technologies and is a companion to the Advanced Technologies Lab Workbook. Each technology you need to know for the CCIE Routing & Switching lab.

How to secure your Cisco Catalyst Switch

Cisco Catalyst switch is fully secured within your network.

1. PASSWORDS

First of all passwords are configured. One password is used for the enable password and the other will later be assigned to the console port.

enable secret  [password]

username admin password [password]