Filtering traffic with vlan access list

Topology Lab setup Linux 2 belongs to vlan 10. Linux 3 and 4 belong to vlan 20. Router is the dhcp server for vlan 10 and 20. A default route goes from Router to the internet where the web application DVWA resides. VLAN 10 subnet 10.10.10.0/24 and VLAN 20 subnet 10.20.20.0/24. Damn Vulnerable Web Application … Continue reading Filtering traffic with vlan access list →

VLAN Trunking Protocol

This is a Cisco proprietary protocol that is designed to ease Vlan database management, it has nothing to do with trunking. The concept is that a switch with a VTP server mode will propagate VLAN database down to all switches with VTP client mode. Sw2-3560 vlan database before a new vlan is added (VTP client) … Continue reading VLAN Trunking Protocol →

Catalyst Switch: Turn off trunking negotiation

To turn off dynamic trunking protocol (DTP) and use dot1q standard. It is recommended to turn off trunking protocol and put vtp to transparent mode, this is because a newly introduced Catalyst switch may form undesired switch topology and if the newly introduced Catalyst switch has a vtp revision number higher than the current switch … Continue reading Catalyst Switch: Turn off trunking negotiation →

Catalyst Switch: No trunks is formed

I have connected two Cisco Catalyst 3560 switches together by a pair of fibre cables. No trunk was formed. The default interface configuration for Catalyst 3560 is dynamic auto, in Catalyst 3550 the default was dynamic desirable. Dynamic desirable is actively negotiating a trunk with another cisco catalyst switch, whereas dynamic auto is passively waiting … Continue reading Catalyst Switch: No trunks is formed →

Security: Private vlan example

Private vlan 1. Before you start make sure the vtp mode is set to transparent. 2. The difference between private vlan and protected port is protected port is localized within the switch itself, but private vlan can propagate among switches. 3. Private vlan consists of primary vlan and secondary vlan. 4. There are two types … Continue reading Security: Private vlan example →