Cisco – Joining Layer 2 Networks Over Layer 3 Networks
KB ID 0001313 Problem It’s a common problem, you want to connect one site to another and still have them on the same layer 2 network. As you can see above both the routers at the bottom are in the 172.16.1.0/24 network, let’s assume they are clients in the same layer 2 network how would you connect them? Solution Option 1: xconnect over L2TP All the ‘heavy lifting’ is done on the SiteA and SiteB routers. We...
Cisco IOS – Enabling LLDP
KB ID 0001289 Problem If you’re running Cisco IOS on all you devices then you can use CDP to see what’s directly connected, (unless you are on a Cisco firewall, but I did say IOS devices). Petes-Switch#show cdp neighbors Capability Codes: R – Router, T – Trans Bridge, B – Source Route Bridge S – Switch, H – Host, I – IGMP, r – Repeater, P – Phone, D – Remote, C...
Cisco Licence Differences LAN-Lite / LAN Base / IP Base / IP Services
KB ID 0001270 Problem Actually finding the answer to this question is far more challenging than it needs to be! As usual Cisco can change this on a whim so before you purchase any equipment it’s still a good policy to check on the feature navigator. Solution This is about the best reference I’ve found. Although anyone who can tell me what the correct Layer 2 differences between Enterprise Access and Complete Access are,...
Cisco IOS – How To Find VLAN IPs (SVI’s)
KB ID 0001258 Problem If you have a complicated network, you can spend more time finding out how it’s configured, than actually doing any work on it! Today I had a client that needed some changes made on their LAN, I knew their name, and their network address, and common sense told me which of the core switches they were connected to. Solution A quick search on the client name told me what VRF they were in, and what VLAN they...
Cisco IOS ‘Crypto’ Unrecognized Command?
KB ID 0001246 Problem I was working on a Cisco 3750-G last week, and I was in the process of setting up SSH access. When I went to generate the crypto key and enable SSH, It fired an error at me. In fact it wouldn’t execute any crypto commands; Core-SW(config)#crypto ? % Unrecognized command Now I have seen this before, (but not for a while). You need to be running a K9 version of the code. A quick ‘show version’...
Cisco Stacking 3750 Switches
KB ID 0001205 Problem You can stack Cisco 3750-X Switches in groups of up to 9 switches, and they can then be managed as one switch. Here I’ve got 2 switches. Solution Removing 3750-X Switches Stack Configuration One of my switches had already been in a stack, so I needed to remove its stack configuration. It thought it was switch 4 in the stack so I issued the following commands; Switch(config)# no switch 4 provision...