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 …
Category Archives: linux
Linux: query remote ntp (and show time difference)
Posted by Roman Pertl on April 19, 2018 No comments
Howto: Disable persistent Network Interface Names (Debian Stretch)
Posted by Roman Pertl on December 7, 2017 No comments
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
Posted by Roman Pertl on September 8, 2016 No comments
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. ↑ …
Running “backticks” commands on remote servers
Posted by Roman Pertl on June 16, 2016 No comments
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 …
Update for the Checklist on “mailout” servers
Posted by Roman Pertl on April 19, 2016 No comments
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 …
Cloudflare and Haproxy Lodbalancer
Posted by Roman Pertl on February 10, 2016 No comments
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 …
Java SSL Certificate Verification Error
Posted by Roman Pertl on January 22, 2016 No comments
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 …
Hardening SSL
Posted by Roman Pertl on January 17, 2014 No comments
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 …
