Networking

Although IPv6 is still fairly unused in the enterprise or home, it is beginning to gain traction, so I thought I should begin to learn about it. These articles there will be a few will chart my investigations into setting up IPv6, starting in this part with two workstations on the same network segment and … Read more

Something I’ve done recently, the switch has been in for over a year, but was put in, in a hurry, and we’d never got round to finishing off the configuration fully until now. It has two processor supervisor blades, but its always been running in RPR mode, as we now run VMware ISCSI traffic through … Read more

I’m only going to show the juicy bits of the config. I.e. the bits that refer to the routing, EIGRP or IP SLA stuff. A user at Site A in normal use should see two default routes to the Internet, one being their local default route, and then the Site B default route, with a … Read more

Wake on LAN packets do not traverse routers (normally) so you need to configure your network to do this. There are some security implications you need to be aware of first, Cisco’s document on it is a good read:http://www.cisco.com/c/en/us/support/docs/switches/catalyst-3750-series-switches/91672-catl3-wol-vlans.html Also download Solarwinds Free Wake On LAN tool, its a good one to use to test … Read more

This is not as easy as it is on a Cisco 3750 or 6500 series switch but once you know how its not too bad. Step 1 Copy the new IOS image to the switch, you need to use: copy tftp: bootflash: (Notice its not “flash:”, first of the oddities.) Step 2 verify the image … Read more

After setting up AAA on all our switches (there’s loads of tutorials on the Internet about this) we had the problem that this also applied to the console port. We didn’t want the risk that a faulty switch could be rendered inaccessible by the AAA and leaving us in a panic about what to do … Read more

We had a severe lightning storm with power cuts and multiple lightbolts hitting our buildings and grounds around our core server rooms. Luckly the UPSes carried the load and gobbled up the overvoltages etc no problem. However the lightning induced an over voltage in the copper cables that run from the Cisco 6509 POE Blades … Read more

In this example the ghost server is on IP address 172.27.5.73/24 and is in vlan 205. The ghostcasting clients (i.e. a workstation I want to re-ghost) is in vlan 240 on IP address: 172.27.240.10. There are two DHCP servers also in vlan 205 on IP addresses 172.27.5.131 and 172.27.5.132. We want the ghostcast client in … Read more

Tried to connect up to a pix using a Cisco VPN Client, the connection connected fine, but when I tried to VNC or RDC to something had no joy. Checking the statistics of the vpn connection on my pc it showed sending traffic but not getting anything back. This is caused by a problem with … Read more

On our Cisco 4500 series switches we could not see when ports where going up or down, even when using “terminal monitor.” We use this technique to identify ports and has been useful in our VLAN project. The problem was that on 4500 series switches, you need to manually enable this type of logging, to … Read more