analyze packet loss with wireshark

Lost packets can extremely slow down a network and even completely bring down at high load.

Poorly laid cables, network segments that are too long (above but also below 100 meters) but also too many switches can cause the network to become out of sync.

With Wireshark you can easily test your own connection for lost packet segments and retransmissions:

  • tcp.analysis.lost_segment – Indicates we’ve seen a gap in sequence numbers in the capture. Packet loss can lead to duplicate ACKs, which leads to retransmissions.
  • tcp.analysis.retransmission – Displays all retransmissions in the capture. A few retransmissions are OK, excessive retransmissions are bad. This usually shows up as slow application performance and/or packet loss to the user.

some lost segments to web destinations are ok, but massive lost packets on connections to a local server are bad.

OSX homebrew: MidnightCommander not working as root

Problem

bash-3.2$root# mc
common.c: unimplemented subshell type 1
read (subshell_pty...): No such file or directory (2)

solution – install newest bash

user$ brew update
user$ brew upgrade
user$ brew install bash
user$ /usr/local/opt/bash/bin/bash
user$ sudo bash -c 'echo /usr/local/opt/bash/bin/bash >> /etc/shells'
user$ chsh -s /usr/local/opt/bash/bin/bash
user$ sudo chsh -s /usr/local/opt/bash/bin/bash

Lenovo Thinkpad L640 – Trackpad unter Linux Mint/Ubuntu aktivieren

/etc/default/grub bearbeitenb und bei GRUB_CMDLINE_LINUX_DEFAULT ein i8042.reset am Ende einfügen.

Neustart und das Trackpad inkl. TouchPoint funktioniert.

Gestestet: Linux Mint 18.3 (sylvia/xenial) und Lenovo Thinkpad L460

Quelle: https://askubuntu.com/questions/740556/trackpoint-and-touchpad-lenovo-l460-thinkpad-15-10

Ein weiterer Bug ist das beim tippen z.B. in LibreOffice das empfindliche Touchpad teilweise die Maus bewegt und klicks auslöst. Da hilft nur Touchpad deaktivieren und ggf. eine externe Maus nutzen.

Wo hat es noch funktioniert? Bitte Linuxversion und Notebook in die Kommentare!