Sometimes when you edit the config on your router you just want a little privacy. So how do you kick off the other users safely and politely whilst protecting and securing your own access? Here are few ideas and walk-throughs for some basic VTY access and administration tasks.First things first - how can we check who is logged in? In my old *nix days I had the 'who' command and IOS has used that same
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How can we mark frames coming from a PC on a switch port when it is daisy chained via an IP phone? Lets go through traffic prioritisation at using CoS markings for two different VLANs. Why two? Well when we configure the port on the switch which the IP Phone will be plugged into we setup a DATA vlan and a VOICE vlan. These 'psuedo trunk' links go up to the phone and then the phone has a PC port on
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OK so Cisco figured there was something wrong with the way we used to do NAT configuration in a PIX/ASA. Personally I have no idea why they did this and frankly the new configuration is very confusing and the ASDM is unusable!In the past we used to use the 'nat', 'global' and 'static' commands but now have the 'nat' configuration command remains. Personally speaking I used to love the phrase 'inside
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I came across an issue with DHCP today. The customer was reporting that none of their machines could access the network. A quick look and it was easy to see that the machiens were not getting IP address information.So jump onto the router and issue the commands:R1# terminal monitorR1# debug ip dhcp server eventsThe first line tells the cisco device to send STDOUT (console logging) to the VTY screen
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Hi Everyone,OK so you've got some IP voice calls running over your WAN circuit and everything (as my Indian friends say) is maja. Now maybe historically everything has been good but today you are getting some complaints about voice quality. The calls are dropped or the remote side is gettgin big delay and blips on voice calls that sound like popcorn cooking (or a fried MP3 encoding). Maybe also
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I've been troubleshooting a phone issue recently which required me to upgrade the firmware. The deal however is that the phone is a few thousand miles away from me across a link with poor connetivity. The remote phone is running a firmware of 8.5 and the Cisco Call Manager is holding a version of 9.1. Upgrading the firmware across the link using TFTP causes huge packet loss and frankly takes about
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This technical article is an attempt to describe the method I used to configure a SIP trunk into Cisco Call Manager Express now called Cisco Unified Call Manager Express. For the benefit of my testing I used a SIP trunk service from voipfone.co.uk. I believe this method should be equally valid for any public SIP provider out there. This is a WORK IN PROGRESS and I'll update it as I go on with it. I
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Anyone starting out in their networking career will come across the loopback interface pretty quickly. So what are they and why do we use them so much? Well, the loopback interface is a logical interface (compared to a physical interface like a Fast Ethernet of Serial interface) and unlike a physical interface carries no electrical status so it is always UP but can be administratively shutdown. The
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Cisco have always re-invented the access-list. From standard to extended, introducing the 'established' TCP SYN 'catch'. Then Reflexive, context based (inspection) and now...the ZFW or Zone Based Firewall (why isn't it ZBF? I have no idea). Since 12.4(6)T we've had a new kid on the block which when I saw it felt very ScreenOS borrowing something from PixOS. The idea is that instead of an interface
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In days of olde when networks were bold and subnets freaked out the support teams, we embraced Proxy ARP (RFC 1027) in a big way. So what are we talking about with Proxy ARP? We're going to dive into it here.Proxy ARP was often used as an excuse to the 'zero-effort networking' club. Enabling proxy ARP allows hosts on the same IP subnet to be segmented beyond the normal layer 3 boundary (i.e. router)
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