Using reverse telnet and ssh

Sometimes I find a need to use a console cable remotely, but getting someone to set up a PC or laptop with a serial connection for remote access can be quite a hassle.   I have used the following configurations to get remote serial access using only an onsite router. Continue reading “Using reverse telnet and ssh”

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Editing Cisco ACLs Inline

Are you annoyed at having to copy an ACL to a text editor to add a line?   After that, you have to either remove the ACL entirely or add the new version with a different name and update all the interfaces to use the new name.  I have been using the following trick recently to edit ACLs inline without having the complete remove or rewrite the ACL.
Continue reading “Editing Cisco ACLs Inline”

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Setting up 802.q and switch ports in an ASR9000

IOS-XR has a structure that is very different than standard IOS. I would recomend checking the different documentation at Cisco.com this post is not going to explain things like having to commit a config before it is applied… etc, but rather I am going to assume you have read the getting started guide.

The project that lead to me being exposed to an ASR9000 is a network migration that is replacing a pair of 7200 routers and a 3750 switch (which is only being used for layer2 features) with a single ASR9000 with Redundant RSPs. The ASR has a 40 port gig module and a 4 port 10 gig module. To replace the switch I need to add ports to a “vlan” and trunk those vlans to downstream switches at other pops. Continue reading “Setting up 802.q and switch ports in an ASR9000”

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Formating Mac addresses using python

UPDATE

A better way to do this is using the netaddr library.  as shown in this post Better way of formatting mac addresses in python

 

I have a large set of shell script that I had written in shell, which I have been converting to python based scripts.  I found using python I could better extend my scripts and reuse code.  I also appreciate that python is a full object oriented programming language, with a very powerful set of standard libraries and many optional third party libraries.
Continue reading “Formating Mac addresses using python”

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Source Based Routing for Multiple Networks

After not having time to write an article for a while, here is the article I promised in the last post.  We will take our basic network from our other article on source based routing, and expand it.  This solution involves a dual-homed network with redundant gateways.   Continue reading “Source Based Routing for Multiple Networks”

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Source Based Routing with Cisco

When you are transitioning from one carrier to another using provider allocated IP space there is a neat little trick you can use to route outbound traffic through the correct carrier.  While there are some carrier’s that do not filter their ingress traffic, there are many others who do.
Continue reading “Source Based Routing with Cisco”

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Translating configs the Geeky Way

This post by Ivan Pepelnjak reminds me of the time I was converting a customer from a Redback to a Cisco who had extensive vpi/pvc settings with statics. I spent about two days working up the scripts, but felt pretty satisfied with my work after I was done. Great write-up Ivan, do you mind sharing the scripts?

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