Problem: You plug in a NodeMCU ESP32 board (from BerryBase in my case) to you computer, but no USB serial port is registered in /dev/. lsusb shows a device called “VeriFone USB to UART Bridge Controller” instead of the expected “CP2102/CP2109 UART Bridge Controller” In this case Ardunio Studio cannot find the module. Solution: thanks …
Problem: After an update of a server to Devuan4/Debian11the switch shuts down the interfaces to the server with status “dcxNoACKi” 48 minutes after the reboot. Discussion: the switch is a Cisco Nexus 5000 switch. It implements “Data Center Bridging Capability Exchange (DCBX)”. The server is a Dell server with X710 Controller 10GbE with i40e drivers. …
Interface down on Cisco Nexus switch with “dcxNoACKi” Read More »
Problem: when you switch between Apple Mac and normal keyboards and use German keyboard layout, you can change the keyboard layout on MacOS to “de standard” to have most characters where you would expect them (e.g. @ { } …) but on german keyboards the “AltGr” is located directly left of the space bar. On …
Problem: if you have Windows and Linux on the same computer, windows shows the wrong time shifted by your timezone (dst) after rebooting from Linux. Discussion: Linux stores UTC in the computers hardware clock usually. This makes multi user, multi timezone, and dst handling easy, because it knows hardware clock is always UTC, and calculates …
Problem: (5. September 2022) when fetching Devuan updates you get the following error: Discussion: The devuan key to sign the repository list has expired on 3. September 2022. This is an embarrassing fail from Devuan. But the solution is quite simple Solution: Install the new keyring manually: Version: tested with Devuan 3 (beowulf), Devuan4 (chimaera)
As an IT professional it’s quite common that have to connect web servers with invalid certificates, for different reasons. For expample opening a management GUI of an appliance may be necessary to change its own certificate or TLS settings. Problem: sometimes chrome won’t let you open this website, and gives you no “Proceed on” button. …
Chrome Won’t Let You Proceed to Website with Invalid Certificate Read More »
Problem: In syslog you find a line like this: But when you check with “smartctl -a” you find a reallocated sector count of zero: Discussion: The harddisk had actually no reallocated sectors, but Smartctrl (Smartmontools) reported a wrong error, because when it was started a different harddisk with errors was found as /dev/sda, but with …
Smartd Reports “Reallocated_Sector_Ct” erroneously Read More »
Problem: When pasting commandos to the shell, the shell no longer executes the command but shows the pasted text highlighted and shows the line feed but does not process it. Discussion: Devuan4 and Debian11 upgraded the readline library with a new default “feature” that should prevent noobs from accidentally pasting commands into the shell. But …
Every Cisco switch has a serial number that shows information about it’s production location and year. As you see this switch is very old and was running very long. Without any issues btw. The serial number here is shown as “Processor board ID”, you might also find “System serial number” or similar. The format is …
Some protocols need more than one TCP or UDP connection. For NAT to work the firewall needs to open additional ports to allow client server connection automatically. Examples are FTP (port 21 handshake, additional ports for data), PPTP (port 1723 for handshake, proto GRE 47 for payload) Since Linux kernel (~) 4.7 these helpers are …