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avril 12, 2017 Christophe Casalegno Aucun commentaire

Comment vérifier si un domaine est bien synchronisé entre 2 serveurs DNS

>Hello World, Parfois il peut être utile de pouvoir vérifier si un domaine est correctement synchronisé sur vos serveurs DNS maître et esclave. Le moyen le plus simple pour y parvenir et de comparer les numéros de série de la zone entre les 2 serveurs dns. On peut utiliser également cette méthode pouvoir voir où …

avril 12, 2017 Christophe Casalegno Aucun commentaire

How to check if a dns zone is synchronized between 2 dns servers

>Hello World, Sometime it can be useful to check if a domain is correctly synchronized on your master and slave dns servers. The easiest way to do this, is to simply compare the serial number between your 2 dns servers. That also can be useful to check about dns propagation in the internet. For doing …

avril 8, 2017 Christophe Casalegno Aucun commentaire

OVH : How to block an ip address on your server if you are behind a Load Balancing IP (LBIP / IPLB)

>Hello World ;) If you use or manage OVH dedicated servers, you probably know this excellent and cheap service : Load Balancing (LBIP or IPLB in French). This is an IP address carried directly by the OVH network which spreads traffic load across the IPs of your OVH dedicated servers / public cloud / private …

mars 27, 2017 Christophe Casalegno 4 commentaires

Mysql : how to purge binary logs when you have no space left on device ?

When you need to purge binary logs on a MySQL server, you just need to connect to your server and use the PURGE BINARY LOGS command like this : For example : Will purge all the binary logs before the date. Other method is to purge log file on « name » attribute of the log file. …

décembre 2, 2016 Christophe Casalegno Aucun commentaire

LXC : a new vulnerability ? No just a display bug !

Sometimes you discovering a vulnerability when you don’t search for and sometimes finally like this, it’s simply a false alert. More than 70 percents of vulnerabilities I’ve found in my life have no rapport with a security research, but simply due to chance, when doing administrator tasks for example. This day, I decide for …

novembre 13, 2016 Christophe Casalegno Aucun commentaire

Bash : how to simply check disk space on linux and take action when a threshold is reached

Hi all, after showing you how to simply check load average or memory usage on linux, today i’ll simply show you how to check disk space and take action if a threshold is reached. We’ll simply use df, grep, awk, cut and if/then to do this : Just put it in your crontab and you’ll …

novembre 6, 2016 Christophe Casalegno Un commentaire

How to simply check free memory and take action when a threshold is reached

In your admin work it can be useful to check free memory and take action on threshold. The most tools don’t show you a realistic state of your memory. For example if you launch « top » command on a server, you’ll obtain an information like this : If you use the « free » command, you’ll obtain the …

novembre 6, 2016 Christophe Casalegno Aucun commentaire

Under WordPress « Pingback » DDoS Attack ? Use iptables

WordPress « Pingback » DDoS attacks can generate a lot of requests to your website that can affect performances and availability. Â You can recognize easily this attacks : you just need to do a tail -f Â on your logs and you’ll probably see thousand of request that have a User-Agent « WordPress xxxx » on it. I don’t think …

juillet 8, 2016 Christophe Casalegno Aucun commentaire

How to quickly remove a lot of dns zones from bind ?

When you work for a MSP, a hosting company or a cloud operator, sometimes you need to delete a lot of dns zone in one time. If you need to delete 1500 zones with your hand and you keyboard, you ‘ll need week to do the job. So let me show you how you can …

mars 1, 2016 Christophe Casalegno 2 commentaires

Automatic bind 9 installer with chroot Debian 8

Hi all, install bind 9 on debian 8 and chroot it isn’t a complicated task. But that’s steal a precious time for doing something else. So this is just a tiny post to simplify you this way First Step : install Debian 8 Second step : Third step : just use wget to download the …

juillet 26, 2015 Christophe Casalegno Aucun commentaire

Serial DNS Updater : how to update automatically serial in dns zonefiles massively (or not)

When you work in a hosting company, DN is probably one of the services with you need to interact every week. With this script you can update automatically one or more of dns zone files : for the serial number : just let bash doing it for u. Because most of time we are not …

juillet 14, 2015 Christophe Casalegno Un commentaire

How to automatically take an action if the load average is too high

When you manage servers, it can be useful to take a numbers of action automatically (restart a service, add a firewall rules, kill a process, sending an alert, etc.) if the load average is too high. The problem of a lot of shell script about this, it’s if the load average down slowly after the …