Bernhard Fischer

Internet and Security Engineer, Open Source Advocate, Software Engineer, Hacktivist, Blogger, Skipper, Sailor.

Most commented posts

  1. Onioncat on Windows — 25 comments
  2. Website Relaunch — 23 comments
  3. OnionCat Mailinglist — 16 comments
  4. OnionCat on Android — 14 comments
  5. Onioncat and Tor Hidden Services V3 — 13 comments

Author's posts


Version 1.0, 2022/07/21, Bernhard R. Fischer <>. Original Source: ABSTRACT Since the beginning of the development of OnionCat in 2008 a lot has changed. Most importantly this is the replacement of Tor’s hidden services version 2 by the new hidden services version 3. This had a severe impact on the functionality of OnionCat. This …

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Onioncat Security Considerations

Onioncat is an add-on for anonymization networks such as Tor and I2P. It adds real IP layer networking capability to hosts connected through Tor. Hence it is not enough to just refer to the security of Tor (or I2P). This article discusses security Considerations which are specific to Onioncat. Of course, since Onioncat relies on …

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Onioncat on Windows

Onioncat ist written in a portable manner, thus it runs on almost all operating systems, even on Windows. This document describes how to run Onioncat on a Windows 10 installation together with the Tor browser bundle. The Windows part of the code was already written in 2008, hence Onioncat on Windows is nothing new. This …

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This is a new version of the Garlicat-HOWTO which I wrote about 10 years ago in November 2009. Actually, this original HOWTO still applies but, anyway, I rewrote it to match the software versions of today, August 2019. This document is based on the I2P router version 0.9.41 and Onioncat 0.2.7, both running on a …

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Onioncat and Tor Hidden Services V3

For security reasons the Tor project introduced hidden services version 3 (HSv3) which facilitate stronger cryptography to comply with modern needs for security. Onioncat was developed with version 2 of hidden services which are still in place work as expected. Unfortunately HSv3 do not integrate smoothly into the OnionCat concept but nevertheless, with a few …

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OnionCat Repository Moved to Github

It was almost exactly 10 years ago that we started to run our OnionCat SVN repository for managing the source code. As of today, the 9th of January 2018, the OnionCat source repository has moved to Github at This also solves the mailing list problem. To be honest, the mailing list never really worked …

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Evading Firewalls With OnionCat

You operate your own server running some web services, a mail submission service, an IMAP service, of course ssh for maintenance and several other services? But unfortunately you cannot reach any ports except 80 and 443 as soon as you are somewhere in a public Wifi because of firewall restrictions? Then OnionCat is your friend …

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OnionCat on Android

This article is about how to compile and run OnionCat on Android. Unfortunately, there is no Android app which simply enables it, due to the lack of programming power.1 But if you are familiar with compiling projects and using ADB and the command line, this should be no big deal for you. Here’s how it …

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OnionCat Mailinglist Up Again!

Sorry, forgot to post this here: the mailing list is up again (since about 2 months 😉 )

OnionCat Mailing List Down!

Unfortunately, we encountered some problems with the mailing list. It will be repaired as soon as possible!