Projects

Have fun browsing my projects. In case you have any questions, don't hesitate to contact me. I'll answer your e-mail as soon as possible!

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Flexoptix SFP transceivers

When working with networks, you have to deal with different devices from different vendors. When it comes to SFP tranceivers, you often need vendor specific transceivers because vendors tend to apply some sort of vendor locks. Despite SFP beeing a standard, you need SFP transceivers from your device's vendor. I found a nice solution to circumvent these requirements.

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2/2 IPSec over GRE with MikroTik's RouterOS and Linux

I finally did it: I wrote the second part...

This is the second part, explaining how to create GRE tunnels between a linux server and a MikroTik Router and encrypt the tunnel using IPSec.

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iptables rule for L2TP over IPSec

One of my readers wrote me and asked how to setup the host firewall on a L2TP/IPSec server to only allow L2TP connections which are IPSec encrypted. Here is how it is done.

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jumpNet topology update March 2018

As I wrote some weeks ago, the jumpNet is now interconnected with dn42. You'll find a new network map in this article.

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Building a L2TP/IPSec server with OSPF routing capability

Over time, jumpNet's VPN servers became bottleknecks regarding bandwidth. Currently, the best VPN server in jumpNet offers 20MBit/s upstream, which is okay but not sufficient for large file transfers like backups. In this article, I describe how to build a L2TP/IPSec VPN server with OSPF rotuing capability.

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Interconnection between jumpNet and dn42

jumpNet is fine - no question. But it's small and some how I got used to it. There is little new to discover (maybe I'm going to realize a point-to-point radio link this summer, but that's another story) and so I decided to follow up an old plan: Connecting the jumpNet to dn42.

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jumpNet topology update in January 2018

Some time ago I moved from Zähringe Straße to Merzhauser Straße. What a lucky coincidence, that I moved into the appartment of one of the jumpNet participants. Time to change the topology of the jumpNet a bit.

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Hardware VLAN with MikroTik Routerboards and RouterOS

I needed a VLAN trunk but had no VLAN capable switches - at least I thought so. After thinking a minute, I remembered my two RB2011. I'll show you how to configure VLAN trunks with them.

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pimp my syslog server or "Setting up a syslog server with syslog-ng, Elasticsearch and Kibana"

The jumpNet grows, so do the logs. A little tired of grepping and tailing and lessing it came handy that I needed a solution for a customer with similar needs. After doing some research in the internet, I came across the so called ESK stack. Elasticsearch, syslog-ng and Kibana. Sure, I heared about Elasticsearch and Kibana, but till then I thought this is some hipster IT crap and - I never was so wrong. (Yeah, there is some prejudice coming with age and experience...)

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ECMP routing - equal-cost multi-path routing

As you propably know, the jumpNet has a redundant VPN infrastructure and is using OSPF. To improve the network design futher, I investigated the possibility of equal-cost multi-pathing. Doing so I needed to tackle a little with the stateful firewall.

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