Linux




Linux ip route command reference by example

ip address - Manage IP address(es) on interfaces ip route - Manage routing table ip link - Link Management Interface Grouping. ip neighbor - Managing ARP table Tunnel interfaces GRE NOTE: All the commands below take effect immediately after you hit Enter, and do NOT survive reboot. ip address - Manage IP address(es …



Free public NTP servers from Google

It has passed somewhat unnoticed but Google have made available to us their free, accessible to all NTP servers. I have been using their DNS servers for years without any issues so will trust their NTP ones as well. So far works just fine. For a single server we can …



RHEL get firewall zones and their interfaces in one go

The firewall-cmd doesn't have an option to show all zones and to which one the server interfaces belong, so here is a one-line to show that: #for ii in `ls /usr/lib/firewalld/zones/`; do echo ${ii%%.xml}: ; firewall-cmd --zone=${ii%%.xml} --list-interfaces; done The output: block: dmz: drop: external …



Change colors of ls output in the bash shell

Usually colorization is put in action via alias : alias ls='ls --color=auto' You can turn off the colors each time you run ls: ls --color=never or change the alias itself to disable fancy colors permanently or even simple \ls . But to change the colors you'd need to cause …



PTR bulk DNS resolver in Perl to see what is in the name

There are many ways to do PTR resolving in bulk, and this is just one of them. It doesn't pretend to be the fastest/coolest/best, the only thing I can claim - it works. # Yuri # 19.02.2013 # this script accepts range of IP addresses to do PTr resolving for …



Bash script to generate random passwords

Here I stumbled on an intro into Bash scripting for NetOps by John Kristoff " Introduction to Shell and Perl scripting for Network Operators" https://www.cymru.com/jtk/talks/nanog54-intro-scripting.pdf and could't help but do it my way. Here it is, bash script that generates random password of printable …



md5 sha256 sha-1 tiger and whirlpool sum checker for Windows

Trying out Amazon AWS Glacier with fastglacier.com as the upload GUI app I looked at few SHA256 sum calculating tools, and found this one by Jesse Kornblum to be the best for Windows. It has some quite useful options like recursive folders calculation, file size limitation, reading file names …



Agressive scans from 69.175.126.170 - HD Moore is trying to save the Internet

I've been seeing this for some time so you will see it soon too. We speak here mostly about SNMP probes coming from a set of very specific IPs. If you do a search on IP you get to the webpage below http://critical.io (web site is not up …



Watch your DNS records day and night with Nagios plugins

Domain records are most visible vulnerable and many time crucial asset of the company. Attackers need not break your firewall protection, find and develop exploits for software running on your server to cut off your company from mails - it is enough for them to cause a change of MX record …



'How to separate inbound and outbound data graphs in Nfsen Netflow tool '

As I said already ( here and here ) for gathering Netflow data, especially with security in mind, I deem Nfsen/nfdump to be the best. And with some easy 2-minutes tweaking I can always make it do exactly what I want. By default when you configure Cisco to export both ingress …