Sometimes you just want to query a remote ntp server (and maybe see the difference between the two clocks). In this case you can use the tool sntp. From the sntp man page: The default is to write the estimated correct local date and time (i.e. not UTC) to the standard output…. use something like: […]
Category Archives: linux
Howto: Disable persistent Network Interface Names (Debian Stretch)
How to disable persistent network interface names in Debian 9 (Stretch) edit /etc/default/grub and change the following line GRUB_CMDLINE_LINUX=”net.ifnames=0 biosdevname=0″ afterwards run “update-grub“
Quickly create a (swap)file on linux
The traditional way for creating a linux swapfile would be using dd to create an empty file e.g. A faster way is to use “fallocate” e.g. 1) http://www.cyberciti.biz/faq/ubuntu-linux-create-add-swap-file/ Don’t forget the usually procedure for swapfiles: References [ + ] 1. ↑ http://www.cyberciti.biz/faq/ubuntu-linux-create-add-swap-file/
Moving to KVM
Since our beloved OpenVZ virutalisation technology is not moving in a direction we are comfortable with, we are currently evaluation several virtualisation technologies. One the the possible options is KVM. This is not a full tutorial about KVM, there are many good tutorials already, e.g. 1)https://www.lisenet.com/2016/getting-started-with-kvm-on-debian-jessie/ or 2)http://linuxnewbieguide.org/?p=1993 or 3)http://xmodulo.com/use-kvm-command-line-debian-ubuntu.html or 4)http://wiki.libvirt.org/page/UbuntuKVMWalkthrough or 5)http://www.cyberciti.biz/faq/how-to-install-kvm-on-ubuntu-linux-14-04/, this […]
Running “backticks” commands on remote servers
Sometimes it’s necessary to run a complex command on a remote server witch also includes some “backticks”. Usually these commands are interpreted by the local shell so you need to use a little trick to force execution on the remote server: ssh this.is.my.beautiful.server ‘( echo `echo “This Command is run on the remote server” ` […]
Update for the Checklist on “mailout” servers
This is an update to the checklist to create a prefect mailout server: Original Checklist Setup DMARC DNS Record to receive mail delivery reports https://www.unlocktheinbox.com/dmarcwizard/ btw: I Just started adding all those settings to my own domain too. Google DKIM signing is still waiting for DNS propagation.
Cloudflare and Haproxy Lodbalancer
We are currently trying out the cloudflare service to protect one of our company service. In front of this service we are using haproxy as SSL endpoint and loadbalancer. Cloudflare adds a number of custom headers1)http://www.linuxorz.com/2014/10/cloudflare-haproxy-get-real-ip/: In order to extract the original client IP in the X_FORWARDD_FOR header, you need to use the following configuration2)http://permalink.gmane.org/gmane.comp.web.haproxy/12019 […]
Java SSL Certificate Verification Error
If you come across the situation, that your java programs are not able to connect to ssl encrypted services, it might be most likely that the java cacerts keystore is empty or not uptodate. This might also be due to a bug in the java (or ca-certificate-java) package 1)https://bugs.launchpad.net/ubuntu/+source/ca-certificates-java/+bug/1396760. In order to fix the issue, […]
Hardening SSL
Update: 2014/01/17: Again a few weeks have past without finishing the article. So I’m going to publish it anyway even it it is unfinished work yet. I also disabled OCSP Stapling again. I’m using StartSSL and I’ve had some issues with their OCSP website. Also the nginx implementation is still not “mature” (see: http://nginx.org/patches/attic/ocsp-stapling/README.txt). There […]