SHARIFUL's TECH BLOG

There is a new kid of VPN is in town which is Wireguard . Recently it has been accepted into the linux kernel code.  So, it may be soon that different vendor start implementing in their networking products. Today I will try to explore it from the perspective of running it as an alternative of SSL/L2TP/PPTP remote access vpn, for accessing central resources from a home network through wireguard vpn tunnel. It is called another name - road warrior setup. I will not go deep into how wireguard works. But introduce it briefly. Interested readers are welcome to google about it. Wireguard is based on UDP protocol and default port is 51820. It authentication is based on private/public key pair. Let's say we have two peers in our road warrior setup - one is wireguard client (remote user) and one is wireguard server (router/firewall running wireguard). A peer will encrypt data with is private key, then the receiving peer will decrypt the data using the sending peer's public key. So...

I always like to work with open source tools. As a network engineer, we need to maintain a device configuration management system where we take backup of configuration for different networking devices like routers, switches, firewalls etc. We want to have our backups ready so that we can restore a device configuration when a device fails or replace with new one or for auditing purpose to track recent configuration changes. Today I will talk about such a open source tools named - Oxidized. Interested readers can have a look at it's GitHub page . It is a network configuration management tool with support for diverse networking equipments. Oxidized is developed with programming language Ruby. It is very configurable, extensible and can be integrated with management tools like Librenms . I will do a two part blog about Oxidized. In this part I will cover basic setup of Oxidized and start taking configuration backup of networking equipments. Network Topology Our topology l...

The other day I have an idea that I want to explore for QnQ just out of fun. We all know how QnQ works. In the QnQ termination switch, we configure the switch port which applies the extra vlan tag for QnQ, we configure that port as access port, allow our QnQ vlan as access vlan on the port  and enable QnQ. With the setup above, the QnQ port is in access mode and we can only have that QnQ vlan active on that switch port. But I want to run that switch port in both trunk and QnQ mode, so that I can carry some extra vlan which will not be double vlan tagged with QnQ. Those vlan will pass QnQ enabled switch port with their original vlan tag (with only one and the original vlan tagg applied). May be explained better with some pictures -  I have vlan 11, 12 and 13 which will be double tagged with QnQ vlan 201. And have vlan 101, which will pass the switch port without QnQ just with original vlan tag 101. If we draw a picture it will look below -  Outer V...