Category Archives: Routers

Configuring Cisco Access Lists

Let’s learn by doing: So from our router (layer 3 device) lets create an  Standard access-list: access-list 1 deny 192.168.5.100 0.0.0.0 – uses wildcard bits instead of subnet mask.  Since we are creating a list in standard range (1-99) that denies the IP shown above. access-list 1 permit 192.168.5.0 0.0.0.255 – would permit the entire… Read More »

Cisco Access Lists Explained

Access-Lists: Access lists can be used for more than just permitting and denying ports and IPs.  The access lists should actually be named as identifier lists which identify types of traffic and if it is allowed or not. They can be used for: Access Control NAT Quality of Service Demand Dial Routing Policy Routing Route… Read More »

Cisco EIGRP Concepts and Configuration

EIGRP is the best routing protocol around IF all of your routers are Cisco (which they probably won’t be).  That being said, it’s still good to know how to use it: Here are the benefits of EIGRP: Backup routes are remembered and allow fast convergence called DUAL (Defused Update ALgorithm)  Simple configuration Flexibility in summarization… Read More »

Cisco: OSPF Configuring and Troubleshooting

Configuring OSPF: Lets start with our first router which will also be our ASBR (Autonomous System Border Router) which advertises our internet connection to the other routers: no router rip – kills RIP on your router router ospf 1 – This enables OSPF on process ID 1 (which process ID to use) network 192.168.1.1 0.0.0.0… Read More »

Cisco Routing – Starting from Scratch

This tutorial will walk you through setting up a new router from scratch and the key commands used in doing so. Keep in mind this information has been blogged about previously but this is the master summary. 1)  Lets start by wiping our config on a pre-configured device: write erase – erases the NVRAM file… Read More »

OSI Model Information

Application (Away) Presentation (Pizza) Session (Sausage) Transport (Throw) UDP/TCP Windowing Segments (Name of packet at this level) Sequencing Network (Not) Packets IP Addresses/Logical Addressing Routing Data Link (Do) Mac Addresses/Physical Addressing Switching Physical (Please)  Network Card Physical Wire

Cisco – File Management

This is a simple tutorial demonstrating how to manage files within your Cisco device and how to move files to/from. Cisco devices contain 4 memory components: RAM – Volitale!  Super fast though and it’s what decisions get made from.  This is where the running config is held. NVRAM – Non Volitale (NV) but not quite… Read More »