Menu Close

Installing full Linux from Windows on USB with persistent storage

This guide will describe how to install a full Linux OS on an USB flash disk with permanent storage feature, i.e. the system does not lost your files after a reboot as usual live distribution does. The system is fully operable OS and transferable to any PC with all your installed and saved stuff.

There are several ways how to do it, for example using two usb keys, or making a bootable live USB key and then performing the installation (as is for example decribed here How to Install Linux OS on USB Drive and Run it On Any PC ).

KIS 2019 network dataset

KIS 2019 network dataset

  • Authors : Jana Uramová, Tomáš Mokoš, Patrik Rodina, Peter Seemann, Miroslav Kohútik

This article describes the KIS 2019 network dataset. If you wish to access this dataset, contact us by e-mail at dataset@kis.fri.uniza.sk.

The KIS 2019 dataset was created by Tomáš Mokoš as a part of his Diploma thesis at the Department of Information Networks on the University of Žilina’s Faculty of Management Science and Informatics.

Tools for a quick SIP diagnostics – ngrep, sipgrep and sngrep

Sometimes there is a need for simple and quick analysis of a SIP server and its call functions. Of course, we should use the well-known tcpdump, mentioned in the article Using tcpdump for SIP diagnostics. However, for some occasional Linux users this may be too difficult and unclear. But actually there exist some simpler utilities, that could work fine, as ngrep, and for me newer, sipgrep and sngrep (love at first sight).

All utils are directly available and can be installed online from Debian repo using apt-get install ngrep sipgrep sngrep.

SIP clients – security features analysis

Table provides the overview of security features of nine analysed open-source SIP clients (some sources call them the RTC communicator).

Source: P. Segeč, M. Moravčík, J. Hrabovský, J. Papán and J. Uramová, “Securing SIP infrastructures with PKI — The analysis,” 2017 15th International Conference on Emerging eLearning Technologies and Applications (ICETA), Stary Smokovec, 2017, pp. 1-8.
doi: 10.1109/ICETA.2017.8102525
URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?rp=&arnumber=8102525&isnumber=8102457

Enabling USB Wi-Fi dongle adapter on VirtualBox VM

When we have Wi-Fi adapter in our PC, we may use it as a network interface of VM, but the VM will recognize it just as another wired interface. But there is possibility to connect an USB Wi-Fi dongle adapter and enable it to the VM. VM then will see dongle as native USB Wi-Fi adapter and it allows to work with WiFi networks natively.

For example, we have the TP-LINK Archer T2UH USB dongle, Windows 10 as base system, Lubuntu 19.04 as the virtual machine and VirtualBox 6.0.8.

Set language on Cisco SPA 502G

This post is relevant to all Cicso SPA phones, which have “G” letter in their names. “G” means global (that you can put there languages), not gigabit ethernet (all phones have 100 Mbps interfaces).

First of all, you need to download language files from cisco support page. They are XML files and look like “spa50x_30x_en_v756.xml”. This is for english language. Important is, that you must have two files – for your desired language and for english language. Then set up TFTP server and put there files.

Problem with a VoIP phone behind NAT – disabling FortiGate SIP ALG

Initial state and observed problems

Observed problems

We had observed a problem, where a SIP phone is registering, but the AOR record indicates, that as a Contact IP address the incorrect and strange private IP address is used. As is shown on following listing:

voip*CLI> pjsip show aor 1765
   Aor:  <Aor..............................................>  <MaxContact>
     Contact:     
   Aor:  1765                                                 1 Contact:  1765/sip:1765@10.16.42.46:65476              f123d14d1c NonQual         nan
 ParameterName        : ParameterValue
  =================================================
  authenticate_qualify : false
  contact              : sip:1765@10.16.42.46:65476
  default_expiration   : 7200
  mailboxes            :
  max_contacts         : 1
  maximum_expiration   : 7200
  minimum_expiration   : 60
  outbound_proxy       :
  qualify_frequency    : 0
  qualify_timeout      : 3.000000
  remove_existing      : true
  support_path         : false
  voicemail_extension  :

This cause a problem, where incoming phone calls (call on 1765 number) are not reaching the SIP phone. We had tried to solve the situations on the phone only modifying its NAT configuration and using STUN, but with no success. Then we setup the lab with two Cisco NAT to simulate the topo. It works perfectly. This indicate on a problem with the Fortigate firewall. Several posts indicates that it could be the SIP ALG problem, which is on Fortigate devices turned on by default and it modifies SIP messages.