Problem: ssh rejects connecting to old servers with this error: Discussion: After upgrading your client operating system, the new installed openssh-client disabled some old ssh key types, but you can enable them with command line options or in ssh_config. Solution 1: Add a command line option: Solution 2: Add a line to your config file […]
Reactivate old SSH host key types Read More »
Problem: you find a key and a cert file on, and need to check if the cert matches the key. Solution: Check the modulo (n=p*q) of both key and cert to see if they are equal. Version: tested with openssl 3.0.11 on devuan 5
How to Check If an RSA Cert Matches an RSA Key Read More »
Problem: After upgrading an old HP ProLiant DL320 G6 Server to Linux kernel 6.1 (Devuan 5, Debian12) the system crashes during reboot. You will see the following kernel output: These errors are repeated several times, and the RAID controller driver “hpsa” for the SmartArray Controller P212 gives up, causing /dev/sda vanish. Discussion: While not absolutely
DMAR Kernel Log Errors and RAID Controller Crash Read More »
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: 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
Windows / Linux Timezone Settings Read More »
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)
Devuan Update Fails with Signature Invalid 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
Devuan4/Debian11 usability annoyances Read More »
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
Linux Connection NAT Helper not Working Read More »
Problem: curl php wget and others show a cert error like the following since 6. Oct 2021, even though the cert has not expired: The asked server uses a Letsencrypt certificate. Discussion: Currently Letsencrypt includes two chains for validation of the certificate: Cert -> R3 -> ISRG Root X1 (in new trust store) Cert ->
Debian Curl/PHP/wget etc show an certificate error falsely Read More »