Month: August 2011

Cisco has weird naming conventions for groups of interfaces

If you want to bind some ethernet interfaces into one logical interface between two ciscos switches you have to configure an interface first: interface Port-channel 1 then add some interfaces into this new interface: interface GigabitEthernet 1/0/1         channel-group 1 mode active and you can check the status with: show etherchannel 1 summary Three names …

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BGP Looking Glass

If you like to search through the full Internet routing table from around the world, you can find some looking glasses at http://www.traceroute.org/ or http://www.routeviews.org/. e.g. Routeviews has telnet access to zebra servers (route-views.isc.routeviews.org,…)

L2TP tunnel between two cisco routers

Problem: a Cisco 1941 [15.1(2)T2] (Client) tries to connect to an Cisco7300 [12.3(22)] (Server) using L2TP, but after successful authentication of the client the server drops the connection. Solution: The client tried to authenticate the server, but the server had no password for authentication. Normally only the client authenticates to the server in ISP environments. …

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Restore data from a single disk of an HP/Compaq SmartArray raid1

If you look into a harddisk from an HP server with smart array configured for raid1, you will recognize that the partition table of this disk has only one partition: Device Boot      Start         End      Blocks   Id  System <device>p3               1           1        8001   12  Compaq diagnostics The real partitions are invisible? No. I found the start of …

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Mysqldump: out of memory

A small mysqldump hint: You can use mysqldump –skip-opt to get proper insert statements in the SQL dump. But –skip-opt disables –quick which means mysqldump buffers full tables before writing -> Out of memory. In this case I use: mysqldump –skip-opt –quick <DBNAME>

Cisco Access Point blocking PPTP

Vienna: 10. August 2011 Problem: A network of some Cisco Access Points AIR-AP1142N-E-K9 connected to an small router works good as expected but when the user tries to connect to en PPTP VPN the connection fails with a time-out. Solution: it was no NAT problem in this case (I fixed this before). Cisco IOS 12.4(21)?? …

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Hello world

My daily job is solving IT problems. No matter if they are hardware/software, or os/configuration/application related. There is always a bug to be fixed. And: AlexT Debugs This blog will be the place to remember some solutions to problems, because as time goes by it’s sometimes hard to remember how I debugged. Some solutions will …

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