Limiting SSH access for dynamic IP source

Summary This post is about a small script that can update the /etc/hosts.allow with single IPv4 for use with Dynamic DNS. Please check the ‘ Warning ‘ section before using the script. If you’ve Server or VPS with public IP and want to limit SSH access (allow or deny) to specific IP or IP range […]

Updated: January 3, 2021 — 1:22 AM

Enabling DKIM on Microsoft Exchange Server 2016

This post relates to my experience and the issues I’ve faced with installing the latest version of ‘Exchange DKIM Signer‘ (on time of writing 3.2.8) on Microsoft Exchange Server 2016 without internet access. In case you are using Microsoft Exchange Server (2007, 2010, 2013, 2016, 2019) and you want to enable DKIM on it, this […]

Updated: December 19, 2020 — 4:38 PM


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This post is general information for next post.In order to make email transaction more secure, below subject can be consider, as part of securing email transaction. SPF DMARC DKIM By transaction, I don’t mean the transfer of email itself but the fact that receiver can be sure they get the right email and the sender […]

Updated: December 18, 2020 — 8:11 PM

Working with ssh keys on Linux servers/cluster

If you’ve Linux servers/cluster and for each user you need to have ssh key for password-less access to different nodes, below script might be useful or be a small hint on what you might be able to get. Scenario which I made below script is a cluster of Linux servers running distributed computing application and […]

Updated: December 14, 2020 — 6:41 PM

Checking bind config & restarting service

I was using bind installed as DNS server in home lab and as I was doing multiple modification, I wanted to if I made any mistake in my configuration, so I made below little script which is supper easy to read and modify; it’ll just show where (which file) issue exist instead of checking manually […]

Updated: December 5, 2020 — 11:24 PM

Monitoring mounted iSCSI/drive in windows using PowerShell

If for any reason you don’t want to use monitoring applications and want to do it by script, well below is small script for monitoring mounted iSCSI or other type of shared drives on Microsoft Windows using PowerShell.In case of drive disappear because of disconnection from provider, it can send and email and also it […]

Updated: December 2, 2020 — 10:58 PM

How to check for “VMSA-2018-0025”

On “2018-10-09” VMware announced a new security advisory “VMSA-2018-0025“. VMware ESXi, Workstation and Fusion contain a denial-of-service vulnerability due to an infinite loop in a 3D-rendering shader. Successfully exploiting this issue may allow an attacker with normal user privileges in the guest to make the VM unresponsive, and in some cases, possibly result other VMs […]

Updated: October 20, 2018 — 5:06 PM

hosts file modification base on network address

There are times, we might have a different networks and for each one we might need different manual IP and name mapping in “hosts” file. Let’s assume we have one iSCSI server (iscsi-srv.test.lab) connected to two different networks (192.168.10.x/24 & 192.168.11.x/24) providing service. For some reason these two network can see each other so if […]

Updated: October 20, 2018 — 3:51 PM

Disabling upload feature for ShareX

There’s a free interesting application called “ShareX” which is great for lots of different tasks such as “screen shot, screen recording, file uploading and etc.”. If you interested on automatically uploads new screen shots online and share, then you might find this application very useful. One of useful feature in this application is the upload […]

Updated: October 20, 2018 — 2:45 PM

SSH & 2FA on Linux

There are multiple ways to make an SSH connection more secure and one of them is adding “Two Factor Authentication (2FA)” to the system and integrate it with ssh connectivity. Here the steps that could help with adding this feature to the system and its integration. This feature could be added to a different distribution […]

Updated: April 15, 2018 — 8:33 PM