Author Archives: pim

Multicasting in a L2 domain

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Multicasting in a L3 domain

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Extending a Debian OpenVPN server with Multi Factor Authentication via Google Authenticator

I know it’s a mouth full.. but the few documents I found on the web were good yet at the same time still left some questions unanswered. So have a look at the PDF and I hope you’ll get it … Continue reading

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Re-instating a revoked OpenVPN certificate

The OpenVPN documentation will tell you how to revoke a user-certificate but NOT how to re-instate one. (or at least I was unable to find it) So here is a recipe on how to do this, using the easy-rsa scripts:

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Subnetting 101

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Calculating DeciBels for eg Wi-Fi networks and the conversion to mW

When calculating DeciBels, bear in mind that it is always a comparative number, eg output as compared to input power. This can be used to compare aerial’s etc. Here are examples of typical dB values: 0dB  =   same power 3dB =      2 *  power … Continue reading

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Creating an IPsec Dynamic VPN / Remote Access VPN on the SRX firewall for the Pulse Secure client, here on OsX

In the PDF below, I describe how to setup a Dynamic / Remote Access IPsec VPN on the Juniper SRX. The client in my case was an OsX machine running Mohave. Pulse secure worked admirably and can be downloaded for … Continue reading

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If ip-monitoring does not work on an SRX cluster..

During a recent project, I built a Juniper SRX cluster where a Reth connected via a LAG to a switch, which in turn is connected it to the Internet. In case of a failure, they Reth should failover to the … Continue reading

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Juniper SRX and Active and Passive FTP port forwarding

As you probably know, FTP comes in two flavours:-Active FTP where data port 20 is used on the Server and the client offers a random port > 1023 to the Server via a “Port” command. Hosting this behind a Juniper … Continue reading

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A solution to the NAT traversal problem between a Nintendo Switch and the Juniper SRX Firewall.

I recently had to solve a problem with my son’s Nintendo Switch where the game called “Splatoon” would not find any Internet players because “there was a NAT traversal problem”. Googling told me the wildest stories from completely exposing the … Continue reading

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