Category: Regex

Sep52017 by Achmad Mardiansyah2 Comments

Why it is a bad idea to drop packets using l7-filter on mikrotik

[caption id="attachment_1079" align="alignleft" width="300"] picture from wikipedia[/caption] This article will explain the effect on RouterOS if you drop packets using l7-filter on mikrotik. As we know from previous articles here, mikrotik supports Regex for pattern matching. one of its purpose to match traffic based on information on layer 7 (application layer). Mikrotik has wiki page that explain how the L7 filter works. and on that page, they already warns user that using l7-filter for dropping packet will increase CPU usage and cause router instability. (more…)

Jan52015 by Achmad Mardiansyah1 Comment

Understanding regex on Mikrotik RouterOS

firewall, layer 7, Regex

[caption id="attachment_1076" align="alignleft" width="209"] image from www.cs.iit.edu[/caption] regex on Mikrotik RouterOS. Regex means regular expression. Is a feature / function to create pattern matcher. because of that capability regex is mostly used on Firewall, routing filter, and anything that is related to pattern matching. So our main job here is to create a pattern and regex has its own symbols to define a pattern. one good page that explains list of regex pattern matcher can be found here. (more…)