Tag Archives: IOS

Configure Cisco IOS 802.1x Supplicant

If you have an intermediate familiarity with Ethernet switching you are more than likely familiar with 802.1x port based authentication. With that assumption let’s assume your environment is locked down tight enough to the point where this security is enabled. Great! However, what if you needed to add another Cisco device to a client facing switch port? Not so great… How do you get the device to authenticate the same way as your PC does? Fortunately the IOS includes a supplicant for 802.1x that will allow us to authenticate just like a wired windows client! Let’s check out the config … Continue reading

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Cisco SSH Console Server

Did you know a Cisco router can be used as a console server? Continue reading

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Cisco IOS Task Automation

If you love your server or desktop operating system’s CLI as much as myself you have probably banged out a few scripts to automate tasks at least a time or two… Did you know you can also script and automate tasks on Cisco IOS networking devices? The options are wrapped around the built in embedded event manager. The embedded event manager, or EEM for short, can track a number of sources including the syslog, SNMP, timers, counters and more. These are called event detectors. When an event is detected a policy can be trigged and some action taken. These actions … Continue reading

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Understanding Prefix Lists

When filtering and manipulating routing protocols and routing updates there are a number of options on the Cisco platforms we as engineers can take advantage of.  In a previous post I briefly discussed the use of standard ACL’s to filter updates.  ACLs filter every packet, or in this case advertised network, that falls within the range is specifies.  This is useful for all or nothing or specific inclusions but does not allow us to us easily filter or permit based on the actual prefix length, ie subnet mask length.  Enter prefix lists. To begin the discussion lets establish a topology … Continue reading

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