System administration, maintanance and management related.
Some time ago I’ve tried to solve a ‘funny’ issue with PowerDNS. It refused to start on one of my backup VPS. After apt-get dist-upgrade, it first stopped to work with very meaningful ‘Failed at step ADDRESS_FAMILIES‘ error. Well, I’ve managed to solve it somehow, but then another ‘funny’ problem popped out…
I encountered this problem again, so let’s write it down to avoid googling it. Problem: PowerDNS fails to start with pdns.service: Failed at step ADDRESS_FAMILIES spawning /usr/sbin/pdns_server: Invalid argument Solution: edit /lib/systemd/system/pdns.service comment out RestrictAddressFamilies comment out ProtectSystem=full possibly kill systemd-resolved systemctl daemon-reload ask yourself again, why are you using debian with systemd on server […]
I’ve hacked together and up-to-date version of Asuswrt Merlin firmware for oldie but goldie Asus RT-N16 router. Beware, this firmware is only intended for use by advanced users.
tinc is a great mesh Virtual Private Network daemon, with just one little glitch (and also some little crypto problems ;-). I find its configuration really tedious and complicated compared to OpenVPN and its possibility to centrally assign IP addresses and push options to clients. I know, that’s the tax for being mesh, but wouldn’t […]
Sometime it’s needed to selectively route specified IPs or networks via different interface – i.e. if you want to route private addresses over VPN (a.k.a split tunnel routing) or to route some public IPs over VPN to unblock some nationally restricted sites (Netflix). Here are simple scripts to achieve this.
If you are trying to access site with self-signed certificate with Firefox 31 (or later) and get Issuer certificate is invalid error (sec_error_ca_cert_invalid), you have to disable new mozilla::pkix certificate verification. In about:config set security.use_mozillapkix_verification = false To find out more about mozilla::pkix and why your firefox just got so super secure and paranoid, that […]
I’ve encountered unusual problem while dumping one of the bigger PostgreSQL databases. Every try to run pg_dump resulted in this: sam@cerberus:~/backup$ pg_dump -v -c js1 >x pg_dump: Error message from server: ERROR: invalid memory alloc request size 18446744073709551613 pg_dump: The command was: COPY job.description (create_time, job_id, content, hash, last_check_time) TO stdout; pg_dump: *** aborted because […]
I’ve made two simple (but useful) disk drive monitoring scripts for collectd exec plugin. You can find them on http://devel.dob.sk/collectd-scripts/. smartmon.sh This script monitors SMART attributes of given disks using smartctl (smartmontools). megamon.sh This one monitors some interesting values of MegaRaid adapter physical drives using MegaCli tool. Description how to use them can be […]
If you are trying to export windows certificate with private key, and windows export wizard provides no such possibility (export with private key is grayed out) because private key has been install as non-exportable (what is the default when importing, what almost nobody changes), there is a great tool mimikatz that makes this possible. Download […]
If you have problem to use subversion under redmine, but svn command itself works ok, the problem might be in incorrect home directory configured for user which is running redmine (can be apache user, fcgi user id…etc). Incorrect here means home directory points to a file instead of directory (ie. /dev/null) . One can reproduce […]