This article gives some great benefits of systemd.
Check a private key & certificate match using openssl on the commandline
With my script check-crt-key.sh
rcs for Centos / RHEL 8
rcs has been removed and isn’t even in EPEL for Centos 8.
However the source RPM for Fedora 31 builds relatively cleanly.
Download, install any dependencies & the rpm build environment &
rpmbuild --rebuild rcs-5.9.4-12.fc31.src.rpm
tdiff – compare directories
tdiff looks very handy – more details & copr repository here
Error: Failed to synchronize cache for repo ‘AppStream’ for Centos 8
Are you getting this for “dnf upgrade” & are you running Centos 8.0.1905?
No repo urls can be found as the minor version has changed. You can fix this by just referencing the major version (8).
Try
cd /etc/yum.repos.d && sed -i.BAK -e 's/$releasever/8/g' *.repo
and try again. You can probably revert the .BAK files after a full dnf upgrade.
High load on Linux? Check for processes in uninterruptible state
ps aux | awk '$8 ~ /D/ { print $0 }'
They may be waiting on I/O.
Auto restart your UMax Hosting VPS
I have a UMax Hosting VPS which is very cheap but also very flakey.
This script (python / selenium) will log in and reboot your VPS – you could tie it to a Icinga Event Command for example.
Reduce DNS load on your pi-hole
By setting a minimum TTL on DNS records:
echo min-cache-ttl=300 | \ sudo tee /etc/dnsmasq.d/99-min-cache-ttl.conf # restart your pi-hole service
Online SAS hosting spammers
I’ve been getting “Property Spam” recently with subject lines like “A showcase of great properties on the Costa del Sol” or “Achieve high rental yields in an up-and-coming UK city”.
These are sent to addresses that have never signed up to any mailing list (but have been sent spam in the past and would be on spammers’ lists). These spammers are hosted by Online SAS and have a very slick operation (reverse DNS records, SPF records, DKIM, “clean” domain names typically registered ~6 months ago). The emails have no contact details, just a tracking link to receive a brochure.
I complained using Online SAS abuse form and just got this:
—————————————————————-
Good afternoon.
My apologies for the interruption
We have removed James from any future mailing
Thank you
Steve Wroblewski
—————————————————————-
Is that this Steve Wroblewski on LinkedIn?
The domains are all registered on Namecheap and the websites just seem to be phishing exercises as the homepages are blank. An example site is http://www.diarioinca.org/showcase/marbella/index.php (deliberately left unlinked).
Anyway, the spam continues as they are using multiple Online SAS servers and fresh domains. Strangely the servers never appear in any RBLs either.
Two new system monitors: check_pressure & check_meminfo
2 scripts I’ve written to monitor Linux system performance: check_pressure & check_meminfo