Vladimir Melnik

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Synchronizing records about the occupied IP-addresses between two CloudStack databases

Sometimes it’s necessary to maintain 2 different CloudStack setups (let’s call them Cloud-A and Cloud-B) sharing the same IP-address ranges. For example, we might need that when we’re building a […]

How to test a TCP-connection

Sometimes it’s not enough to estimate the packet loss ratio only, but to make sure that a TCP-connections are stable. Run the “server” instance (sockping -m server -p 65513) on […]

How to determine on which hop your datagrams are being lost without the mtr utility

Sometimes you need to detect which host loses IP-packets being sent by you. It’s good when you can use the mtr utility, but what to do if you can’t install it?

IP-address Round-Robin for Postifx

Here’s a short and pretty self-desctriptive recipe to make your Postfix to send outgoing messages from different IP-addresses switching them on a round-robin basis. First of all, we’ll need the […]

A simple todo list for your shell

This simple script lists today’s tasks every time you log in (or create a new window in your screen).

Adding a new task is as easy as typing something […]

How to check some host by arping without looking up the corresponding network interface?

Sometimes you have to check if some host replies on ARP “who-has” requests instead of simply pinging it. You probably need it when the host has its firewall configured to […]

How to restart some service when server’s load average goes high as fuck

This post’s name and script’s comments are pretty descriptive, right? 🙂

Of course, you can get all further updates of this script from GitHub: https://gist.github.com/melnik13/04225e4e60a8d66f9ab6. Now you can sleep […]

How to run commands on different servers with different login credentials

Wouldn’t it be lovely if you could run some command on a bunch of servers? Of course, you can! Most of us would do something like that:

But what […]

How to monitor which files are growing faster than other ones?

If you ever needed a tool to get to know which files are growing faster than other ones, you probably will be quite satisfied with this simple bash-script.

Simply […]