Netflows. From nothing to flowenricher: My journey for visibility in my network

It all started, as it often does, with a simple hosting setup on dedicated servers, hosting customers on the usual suspects: Hetzner, OVH, and the like. As things grew, the natural evolution was to dive deeper into infrastructure — first a few racks in a datacenter (Nova), then IPs and circuits from a provider, and … Read more

kibana nginx proxy

server { listen 80; server_name kibana; error_log /var/log/nginx/kibana.error.log; access_log /var/log/nginx/kibana.access.log;   location / { rewrite ^/(.*) /$1 break; proxy_ignore_client_abort on; proxy_pass http://localhost:5601; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Host $http_host; } }

VM online resize

No need to rescue / reboot or anything. yum install cloud-utils-growpart growpart /dev/sda 1 resize2fs /dev/sda1 resize2fs 1.46.5 (30-Dec-2021) Filesystem at /dev/sda1 is mounted on /; on-line resizing required old_desc_blocks = 16, new_desc_blocks = 28 The filesystem on /dev/sda1 is now 58719995 (4k) blocks long.

Dealing with igb nic driver dropping network

The problem looks like the device ‘disappears’ from the bus, and becomes inaccessible to the driver. If it happens early – the driver will not load, if it happens later – it may fail with sporadic access errors cat /sys/module/pcie_aspm/parameters/policy grubby –update-kernel ALL –args “pcie_aspm.policy=performance pcie_port_pm=off pcie_aspm=off” dracut -f ethtool -K eno1 tso off gso … Read more

Set Up Automatic Update (Unattended Upgrades) on Ubuntu + Kernel reboots

Configure Automatic Security Update (Unattended Upgrades) on Ubuntu Server First, install the unattended-upgrades package. sudo apt update sudo apt install unattended-upgrades You need to install the update-notifier-common package in order to set up automatic reboot. sudo apt install update-notifier-common Then edit the 50unattended-upgrades file. sudo nano /etc/apt/apt.conf.d/50unattended-upgrades In this file, you can configure what packages should be automatically updated. By default, … Read more

DNSBL: how does it work, and how to create and build an own

A DNSBL is a DNS based [DNS = Domain Name System] blackhole list, which can be used as countermeasure against unwanted mail spam. One of the most efficient ways to block mail spam is to do it on mail server level by denying incoming connects from spam sources, where the contacting remote machine is identified by its IP address … Read more

Building a Poor Man’s Barracuda – cPanel edition

This article will show you how to replicate most of the functionality of a Barracuda Spam Firewall on you cPanel server. The BSF has 12 layers that messages would be process through as illustrated in the graphic below. I’ll show you how to replicate most of these steps using customizations to the Exim and Spam Assassin. This … Read more