Tag Archives: Cisco IOS

ARP Timeout in Cisco IOS

If you’re managing Cisco IOS routers, you might want to adjust the settings for ARP cache timeout. The default value is 4 hours which can be a long time to wait if you are changing out hardware and using the … Continue reading

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Cisco Integrated Service Router QOS with Switch Module

The Cisco Integrated Service Router (ISR) product line has the option to include switch ports using either a fixed-port configuration on low-end models, or switch modules on higher-end ISR routers. The newer second generation (G2) routers support gigabit switch ports. … Continue reading

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Cisco IOS *Not* Secure By Default

This should not be a surprise to other network administrators out there, but the Cisco IOS network device operating system is *not* secure by default. You need to make sure to take extra steps to lock your device down for … Continue reading

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Recent IPv6 Features for Cisco IOS

As more companies begin planning for an upcoming IPv6 transition, it is helpful to review the status of software IPv6 support from your network vendor. Here I will attempt to list a few recent updates in Cisco IOS that may … Continue reading

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Cisco IOS Clock

Your network equipment should be configured with the right time, and if appropriate – the right time zone as well. Here are some commands that may be helpful if you’re setting the clock on your Cisco IOS network gear. US … Continue reading

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Quick Save of Cisco IOS Running Config

I’ve seen Cisco support use this technique over the phone a few times and think it is useful enough to post here for quick reference. The scenario is that you have terminal access (possibly via serial console) to a Cisco … Continue reading

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Cisco IOS SSH Server

Security-minded network administrators like to manage network equipment using encrypted protocols such as SSH. Cisco IOS routers and switches often require extra configuration to enable SSH. As always, refer to official Cisco IOS SSH documentation for a much more authoritative … Continue reading

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DHCP Server in Cisco IOS

Cisco IOS provides a basic DHCP server that can be useful for testing or small networks. If you’re in an Active Directory environment I recommend providing DHCP service from your domain controller systems and using the “ip helper-address” command (dhcp … Continue reading

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