Cisco ASA EZVPN (Revisited)
KB ID 0001261 Problem EZVPN is a technology that lets you form an ISAKMP/IPSEC VPN tunnel from a site with a dynamically assigned IP (EZVPN Client,) back to a device with a static IP (EZVPN Server). I’ve called this EZVPN revisited, because this is a technology I’ve talked about before. So why am I here again? Well back then I used the ASDM. If you do that now, you need to go in and mess about with things to get it to work...
Cisco Error ‘%PHY-4-SFP_NOT_SUPPORTED’
KB ID 0001347 Problem This is another question I see getting asked a lot in forums! You see something like the following; 000032: *Sep 28 09:35:32.507 UTC: %PHY-4-SFP_NOT_SUPPORTED: The SFP in Gi3/0/50 is not supported (PNL-3750-Stack) 000033: *Sep 28 09:35:32.507 UTC: %PM-4-ERR_DISABLE: gbic-invalid error detected on Gi3/0/50, putting Gi3/0/50 in err-disable state (PNL-3750-Stack) The usual response is ‘Enable unsupported...
Setup RANCID and ViewVC (Part Two) Adding Cisco Devices
KB ID 0001332 Problem Before on Part One we setup our RANCID and ViewVC server ready to start backing up our devices, now we will look at adding the devices, and automating the backup process. Solution To add a Cisco device you need to do TWO things*. Firstly you need to add and entry in the ‘router.db’ file that lives in the ‘Group’ folder you created back in part one. Secondly you need to add the access...
Setup RANCID and ViewVC (Part One)
KB ID 0001331 Problem There are couple of good posts out there on setting up Rancid (Really Awesome New Cisco Config Differ). Some even show you how to set it up with ViewVC (Formally ViewVCS, basically a nice web based GUI front end, that does version control and highlights differences). It does this using a system called CVS (Concurrent Version System, hence the original name.) Then I had to do some more searching to get it to back...
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’...
Microsoft Azure To Cisco ISR Router Site to Site VPN
KB ID 0001220 Problem Last week I was having problems getting a VPN up from a client’s Cisco ASA into Azure. This was because the Azure estate was using ‘route-based’ or a ‘dynamic routing VPN’. See the following article; Azure to Cisco VPN – ‘Failed to allocate PSH from platform’ So the firewall was a non-starter, but Cisco ISR routers are supported, and they can handle virtual tunnel interfaces...