From the monthly archives: November 2008

Cisco hidden tool: test crash

By On November 13, 2008 · Leave a Comment

This is pretty old trick, so maybe  you already know it, but for the rest of you, it can be interresting.

You just had a crash on you Cisco hardware and you have the logs, but don’t know exactly what caused this crash. You tried to have the device crash again, to compare the logs [...]

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Frame-Relay: PVC test with ping to own interface

By On November 13, 2008 · 3 Comments

Let’s say that you have a link configured with Frame-Relay and from time to time you observe that the link is having some strange problems. Since you cannot be sure that the link is provided 100% error free you want to do your own tests. You want to see if the Frame-Relay between R0 and [...]

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Cisco hidden tools: Testing TCP connection

By On November 12, 2008 · 1 Comment

Sometimes you have a connection between 2 routers that you want to test with something more than a ping. Cisco devices have a hidden command which is actually a very powerful testing tool for your TCP connection.

The command is “ttcp” and you will not find it in the the default list of commands of [...]

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How to force Loopack interface to be advertised with a /24 netmask

By On November 12, 2008 · 2 Comments

Many of you already know that usually when you advertise a Loopback interface into OSPF it is advertised with /32 netmask (one IP address) even if the IP address under Loopback interface is with a /24 netmask. If you checked my previous post, you’ll see at the end that I’m right, and the Lo0 address [...]

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How to advertise subnet into OSPF without network or redistribution command

By On November 11, 2008 · 5 Comments

During my CCIE R&S preparation for lab exam, I encounter a task that requested me to advertise a subnet into OSPF routing protocol, but without using network statement or redistribution command. Since back then I was a little confuse about this, I said to post here maybe it help others.

Please download the topology used [...]

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Dynamips: How to save vlans after switch reload

By On November 11, 2008 · 3 Comments

Most of you already know that in Dynamips after a reload of a switch all the vlans and vtp configurations are gone. There is a way how to save the vlan and vtp configuration even in case of a reload of the switch and I will show you below how to do it. For switch [...]

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