LS Style After Devuan 3 or Debian 10 Update

After Devuan 3 update ls output showed characters, that are not really in the directory listing. The reason is that “ls” draws quotes around filenames with spaces. This is a bug from my point of view, ls should never change the actual filenames. If a filename has quotes or double quotes it’s even weirder . …

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Time Format after Devuan 3 and Debian 10 Update

After updating to Devuan 3 the date command shows 12hours am/pm but my days have 24 hours. The locale was always en_US.UTF8 to keep sane command and error output. Debian 10 thinks they had to fix the correct hour display to the complicated one. Therefor all sysadmins like me have to apply the following workaround, …

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Mikrotik OSPF Routing Distance Ignored

Discussion: Every routing protocol has a default distance to help the router to decide which route to use in case of multiple routes for the same destination. For Mikrotik routers these distances are listed here:https://wiki.mikrotik.com/wiki/Manual:Route_Selection_Algorithm_in_RouterOSIf you want to configure a backup link that is only activated when the OSPF main route is missing, you can …

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ARP and Broadcast Packets Missing

Problem: A Linux box with Debian 9 (kernel 4.9) on a HP server with Intel i40e (X710) network cards, is not reachable from neighbor machines, because ARP does not work. Discussion: while testing with tcpdump ARP worked, but later ARP stopped working again. When tcpdump is used with “-p” (non promiscuous mode) you can see …

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MITMProxy and IOS 13

Problem: if you want to debug a IOS app with MITMProxy, the iPhone needs to trust the MITMProxy CA. This is done by going to http://mitm.it/ and clicking on the apple symbol. Then you have to accept the “profile” in Settings “downloaded profiles”. Then you have to trust this new CA cert in “Settings” “General” …

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Linux Live-boot Fails after Debian/Devuan Update

Problem: after updating from Debian 8 to Devuan 2 the overlay live-boot failes with “no such device” Discussion: I use a bootable USB stick combined with live-boot. In this case the USB stick partition 3 is a normal ext4 file system used as read only “plainroot” filesystem. Live-boot overlays this with an ramfs.As I don’t …

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Greenlock(-express) Letsencrypt Fails with ECONNRESET

Problem: after upgrading vom greenlock-express v2.0 to v2.5 and switching from acme-v1 to acme-v2 every attempt to register a new TLS cert with Letsencrypt fails with “ECONNRESET” Discussion: the new version of greenlock tries to validate the .well-known/acme-challenge file before asking letsencrypt for the certificate.If your webserver is behind a loadbalancer or firewall and the …

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Apache Start Hangs during Reboot of a KVM Virtual Server

Problem: Apache needs very long to start on a virtual server running on a KVM/QEMU virtual maschine. Solution: Apache needs a RNG (random number generator) for startup, probably because of TLS. A pure virtual maschine has no RNG device per default. If you add an RNG device to the virtual maschine configuration, apache startup is …

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Sparse Files Howto

Unix file systems like ext3/4 can store files which are partly empty more efficiently by not storing blocks with all zeros. These files are called sparse files. When reading these files every things works as normal but “all zero” blocks don’t wast space on the drive. This can be useful for different application. For example …

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